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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>Global File System</title><link rel="stylesheet" type="text/css" href="Common_Content/css/default.css" /><link rel="stylesheet" media="print" href="Common_Content/css/print.css" type="text/css" /><meta name="generator" content="publican 2.8" /><meta name="package" content="Red_Hat_Enterprise_Linux-Global_File_System-5-mr-IN-4-30" /><meta name="description" content="This book provides information about configuring, and maintaining Red Hat GFS (Red Hat Global File System) for Red Hat Enterprise Linux 5." /></head><body class="desktop "><p id="title"><a class="left" href="http://www.redhat.com"><img src="Common_Content/images/image_left.png" alt="Product Site" /></a><a class="right" href="http://docs.redhat.com"><img src="Common_Content/images/image_right.png" alt="Documentation Site" /></a></p><div xml:lang="mr-IN" class="book" id="index" lang="mr-IN"><div class="titlepage"><div><div class="producttitle"><span class="productname">Red Hat Enterprise Linux</span> <span class="productnumber">5</span></div><div><h1 class="title">Global File System</h1></div><div><h2 class="subtitle">Red Hat Global File System</h2></div><p class="edition">आवृत्ती 4</p><div><h3 class="corpauthor">
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Copyright <span class="trademark"></span>© 2012 Red Hat, Inc.
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The text of and illustrations in this document are licensed by Red Hat under a Creative Commons Attribution–Share Alike 3.0 Unported license ("CC-BY-SA"). An explanation of CC-BY-SA is available at <a href="http://creativecommons.org/licenses/by-sa/3.0/">http://creativecommons.org/licenses/by-sa/3.0/</a>. In accordance with CC-BY-SA, if you distribute this document or an adaptation of it, you must provide the URL for the original version.
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</div></div></div><div><div class="abstract"><h6>सारांश</h6><div class="para">
This book provides information about configuring, and maintaining Red Hat GFS (Red Hat Global File System) for Red Hat Enterprise Linux 5.
</div></div></div></div><hr /></div><div class="toc"><dl><dt><span class="preface"><a href="#ch-intro-GFS">Introduction</a></span></dt><dd><dl><dt><span class="section"><a href="#s1-intro-audience-GFS">1. Audience</a></span></dt><dt><span class="section"><a href="#Related_Documentation-GFS">2. Related Documentation</a></span></dt><dt><span class="section"><a href="#id620191">3. दस्तऐवज नियमावली</a></span></dt><dd><dl><dt><span class="section"><a href="#id620165">3.1. टायपोग्राफीक नियमावली</a></span></dt><dt><span class="section"><a href="#id563161">3.2. पूल्ल-कोट् नियमावली</a></span></dt><dt><span class="section"><a href="#id563272">3.3. टिप व सावधानता</a></span></dt></dl></dd><dt><span class="section"><a href="#s1-intro-feedback-GFS">4. Feedback</a></span></dt></dl></dd><dt><span class="chapter"><a href="#ch-overview-GFS">1. GFS Overview</a></span></dt><dd><dl><dt><span class="section"><a href="#s1-ov-newfeatures-GFS">1.1. New and Changed Features</a></span></dt><dt><span class="section"><a href="#s1-ov-perform-GFS">1.2. Performance, Scalability, and Economy</a></span></dt><dd><dl><dt><span class="section"><a href="#s2-ov-superior-GFS">1.2.1. Superior Performance and Scalability</a></span></dt><dt><span class="section"><a href="#s2-ov-economy-GFS">1.2.2. Economy and Performance</a></span></dt></dl></dd><dt><span class="section"><a href="#s1-ov-subsystems-GFS">1.3. GFS Software Components</a></span></dt><dt><span class="section"><a href="#s1-ov-preconfig-GFS">1.4. Before Setting Up GFS</a></span></dt></dl></dd><dt><span class="chapter"><a href="#ch-config">2. Getting Started</a></span></dt><dd><dl><dt><span class="section"><a href="#s1-config-prereq">2.1. Prerequisite Tasks</a></span></dt><dt><span class="section"><a href="#s1-config-tasks">2.2. Initial Setup Tasks</a></span></dt></dl></dd><dt><span class="chapter"><a href="#ch-manage">3. Managing GFS</a></span></dt><dd><dl><dt><span class="section"><a href="#s1-manage-makefs">3.1. Creating a File System</a></span></dt><dt><span class="section"><a href="#s1-manage-mountfs">3.2. Mounting a File System</a></span></dt><dt><span class="section"><a href="#s1-manage-unmountfs">3.3. Unmounting a File System</a></span></dt><dt><span class="section"><a href="#s1-mount-considerations">3.4. Special Considerations when Mounting GFS File Systems</a></span></dt><dt><span class="section"><a href="#s1-manage-tunables">3.5. Displaying GFS Tunable Parameters</a></span></dt><dt><span class="section"><a href="#s1-manage-quota">3.6. GFS Quota Management</a></span></dt><dd><dl><dt><span class="section"><a href="#s2-manage-setquota">3.6.1. Setting Quotas</a></span></dt><dt><span class="section"><a href="#s2-manage-displayquota">3.6.2. Displaying Quota Limits and Usage</a></span></dt><dt><span class="section"><a href="#s2-manage-synchquota">3.6.3. Synchronizing Quotas</a></span></dt><dt><span class="section"><a href="#s2-manage-enablequota">3.6.4. Disabling/Enabling Quota Enforcement</a></span></dt><dt><span class="section"><a href="#s2-manage-quotaaccount">3.6.5. Disabling/Enabling Quota Accounting</a></span></dt></dl></dd><dt><span class="section"><a href="#s1-manage-growfs">3.7. Growing a File System</a></span></dt><dt><span class="section"><a href="#s1-manage-addjournalfs">3.8. Adding Journals to a File System</a></span></dt><dt><span class="section"><a href="#s1-manage-direct-io">3.9. Direct I/O</a></span></dt><dd><dl><dt><span class="section"><a href="#s2-manage-odirect">3.9.1. <code class="option">O_DIRECT</code></a></span></dt><dt><span class="section"><a href="#s2-manage-fileattribute">3.9.2. GFS File Attribute</a></span></dt><dt><span class="section"><a href="#s2-manage-dirattribute">3.9.3. GFS Directory Attribute</a></span></dt></dl></dd><dt><span class="section"><a href="#s1-manage-data-journal">3.10. Data Journaling</a></span></dt><dt><span class="section"><a href="#s1-manage-atimeconf">3.11. Configuring <code class="command">atime</code> Updates</a></span></dt><dd><dl><dt><span class="section"><a href="#s2-manage-mountnoatime">3.11.1. Mount with <code class="command">noatime</code></a></span></dt><dt><span class="section"><a href="#s2-manage-tuneatime">3.11.2. Tune GFS <code class="command">atime</code> Quantum</a></span></dt></dl></dd><dt><span class="section"><a href="#s1-manage-suspendfs">3.12. Suspending Activity on a File System</a></span></dt><dt><span class="section"><a href="#s1-manage-displaystats">3.13. Displaying Extended GFS Information and Statistics</a></span></dt><dd><dl><dt><span class="section"><a href="#s2-manage-displayspace">3.13.1. Displaying GFS Space Usage</a></span></dt><dt><span class="section"><a href="#s1-manage-displaycounts">3.13.2. Displaying GFS Counters</a></span></dt><dt><span class="section"><a href="#s1-manage-displayexstat">3.13.3. Displaying Extended Status</a></span></dt></dl></dd><dt><span class="section"><a href="#s1-manage-repairfs">3.14. Repairing a File System</a></span></dt><dt><span class="section"><a href="#s1-manage-pathnames">3.15. Context-Dependent Path Names</a></span></dt><dt><span class="section"><a href="#s1-manage-gfswithdraw">3.16. The GFS Withdraw Function</a></span></dt></dl></dd><dt><span class="appendix"><a href="#appe-Publican-Revision_History">A. Revision History</a></span></dt><dt><span class="index"><a href="#id339920">इंडेक्स्</a></span></dt></dl></div><div xml:lang="mr-IN" class="preface" id="ch-intro-GFS" lang="mr-IN"><div class="titlepage"><div><div><h1 class="title">Introduction</h1></div></div></div><a id="id588143" class="indexterm"></a><a id="id588111" class="indexterm"></a><div class="para">
The <em class="citetitle">Global File System Configuration and Administration</em> document provides information about configuring and maintaining Red Hat GFS (Red Hat Global File System). A GFS file system can be implemented in a standalone system or as part of a cluster configuration. For information about Red Hat Cluster Suite refer to <em class="citetitle">Red Hat Cluster Suite Overview</em> and <em class="citetitle">Configuring and Managing a Red Hat Cluster</em>.
</div><div class="para">
HTML and PDF versions of all the official Red Hat Enterprise Linux manuals and release notes are available online at <a href="http://docs.redhat.com/docs/en-US/index.html">http://docs.redhat.com/docs/en-US/index.html</a>.
</div><div class="section" id="s1-intro-audience-GFS"><div class="titlepage"><div><div><h2 class="title" id="s1-intro-audience-GFS">1. Audience</h2></div></div></div><a id="id588063" class="indexterm"></a><a id="id588041" class="indexterm"></a><div class="para">
This book is intended primarily for Linux system administrators who are familiar with the following activities:
</div><div class="itemizedlist"><ul><li class="listitem"><div class="para">
Linux system administration procedures, including kernel configuration
</div></li><li class="listitem"><div class="para">
Installation and configuration of shared storage networks, such as Fibre Channel SANs
</div></li></ul></div></div><div class="section" id="Related_Documentation-GFS"><div class="titlepage"><div><div><h2 class="title" id="Related_Documentation-GFS">2. Related Documentation</h2></div></div></div><div class="para">
For more information about using Red Hat Enterprise Linux, refer to the following resources:
</div><div class="itemizedlist"><ul><li class="listitem"><div class="para">
<em class="citetitle">Red Hat Enterprise Linux Installation Guide</em> — Provides information regarding installation of Red Hat Enterprise Linux 5.
</div></li><li class="listitem"><div class="para">
<em class="citetitle">Red Hat Enterprise Linux Deployment Guide</em> — Provides information regarding the deployment, configuration and administration of Red Hat Enterprise Linux 5.
</div></li></ul></div><div class="para">
For more information about Red Hat Cluster Suite for Red Hat Enterprise Linux 5, refer to the following resources:
</div><div class="itemizedlist"><ul><li class="listitem"><div class="para">
<em class="citetitle">Red Hat Cluster Suite Overview</em> — Provides a high level overview of the Red Hat Cluster Suite.
</div></li><li class="listitem"><div class="para">
<em class="citetitle">Configuring and Managing a Red Hat Cluster</em> — Provides information about installing, configuring and managing Red Hat Cluster components.
</div></li><li class="listitem"><div class="para">
<em class="citetitle">Logical Volume Manager Administration</em> — Provides a description of the Logical Volume Manager (LVM), including information on running LVM in a clustered environment.
</div></li><li class="listitem"><div class="para">
<em class="citetitle">Global File System 2: Configuration and Administration</em> — Provides information about installing, configuring, and maintaining Red Hat GFS2 (Red Hat Global File System 2).
</div></li><li class="listitem"><div class="para">
<em class="citetitle">Using Device-Mapper Multipath</em> — Provides information about using the Device-Mapper Multipath feature of Red Hat Enterprise Linux 5.
</div></li><li class="listitem"><div class="para">
<em class="citetitle">Using GNBD with Global File System</em> — Provides an overview on using Global Network Block Device (GNBD) with Red Hat GFS.
</div></li><li class="listitem"><div class="para">
<em class="citetitle">Linux Virtual Server Administration</em> — Provides information on configuring high-performance systems and services with the Linux Virtual Server (LVS).
</div></li><li class="listitem"><div class="para">
<em class="citetitle">Red Hat Cluster Suite Release Notes</em> — Provides information about the current release of Red Hat Cluster Suite.
</div></li></ul></div><div class="para">
Red Hat Cluster Suite documentation and other Red Hat documents are available in HTML, PDF, and RPM versions on the Red Hat Enterprise Linux Documentation CD and online at <a href="http://www.redhat.com/docs/">http://www.redhat.com/docs/</a>.
</div></div><div xml:lang="mr-IN" class="section" lang="mr-IN"><div class="titlepage"><div><div><h2 class="title" id="id620191">3. दस्तऐवज नियमावली</h2></div></div></div><div class="para">
ठराविक शब्द व वाक्यरचना ठळक करण्याकरीता व ठराविक माहितीकडे लक्ष वेधण्याकरीता ही पुस्तिका विविध नियमावली वापरते.
</div><div class="para">
PDF व पेपर आवृत्ती अंतर्गत, ही पुस्तिका <a href="https://fedorahosted.org/liberation-fonts/">लिबरेशन फॉन्ट</a> संच पासूनचे टाइपफेसचा वापर करते. लिबरेशन फॉन्ट संच प्रणालीवर प्रतिष्ठापीत असल्यास त्याचा वापर HTML आवृत्तीतही केला जाऊ शकतो. तसे नसल्यास, वैक्लपिक परंतु समान टाइपफेस दर्शविले जाते. टिप: Red Hat Enterprise Linux 5 व पुढिल आवृत्ती अंतर्गत लिबरेशन फॉन्ट मुलभूतरित्या निश्चित केले जाते.
</div><div class="section"><div class="titlepage"><div><div><h3 class="title" id="id620165">3.1. टायपोग्राफीक नियमावली</h3></div></div></div><div class="para">
ठराविक शब्द व वाक्यरचना करीता लक्ष वेधण्याकरीता चार टायपोग्राफिक नियमावली वापरले जाते. या नियमावली, व त्याच्याशी संबंधीत लागू करण्याजोगी वातावरण, खालिल नुरूप आहेत.
</div><div class="para">
<code class="literal">मोनो-स्पेस्ड् बोल्ड</code>
</div><div class="para">
प्रणाली इन्पुट, सर्व शेल आदेश, फाइलचे नावे व मार्ग ठळक करण्यासाठी वापरले जाते. किकॅप्स् व कि-प्रकार ठळक करण्यासाठी देखील वापरले जाते. उदाहरणार्थ:
</div><div class="blockquote"><blockquote class="blockquote"><div class="para">
वर्तमान कार्यरत संचयीका अंतर्गत <code class="filename"><code class="filename">my_next_bestselling_novel</code></code> फाइलचे अनुक्रम पाहण्याकरीता, शेल प्रॉम्पट वर <code class="command">cat my_next_bestselling_novel</code> प्रविष्ट करा व आदेश चालविण्याकरीता <span class="keycap"><strong>Enter</strong></span> आदेश चालवा.
</div></blockquote></div><div class="para">
वरीलमध्ये पाइलचे नाव, शेल आदेश व किकॅपचे समावेश आहे, सर्व मोनो-स्पेस्ड् बोल्ड मध्ये प्रस्तुत केले जातात व सगळ्यांचे संदर्भ वेगळे आढळतात.
</div><div class="para">
कि जोडणी प्रकारसाठी हायफन द्वारे प्रत्येक कि जोडणी प्रकार किकॅप्स् पासून वेगळू करणे शक्य आहे. उहाहरणार्थ:
</div><div class="blockquote"><blockquote class="blockquote"><div class="para">
आदेश चालविण्याकरीता <span class="keycap"><strong>Enter</strong></span> दाबा.
</div><div class="para">
प्रथम आभासी टर्मिनलवर जाण्याकरीता <span class="keycap"><strong>Ctrl</strong></span>+<span class="keycap"><strong>Alt</strong></span>+<span class="keycap"><strong>F2</strong></span> दाबा. X-Windows सत्रकडे जाण्याकरीता<span class="keycap"><strong>Ctrl</strong></span>+<span class="keycap"><strong>Alt</strong></span>+<span class="keycap"><strong>F1</strong></span> दाबा .
</div></blockquote></div><div class="para">
पहिला परिच्छेद दाबण्याजोगी ठराविक किकॅप ठळक करतो. दुसरा दोन कि प्रकार ठळक करतो (प्रत्येक संचामध्ये तीन किकॅप्स् असतात व प्रत्येक संच तीनवेळा लागोपाठ दाबला जातो).
</div><div class="para">
सोअर्स् कोडचा उल्लेख केल्यावर परिच्छेदातील, क्लास्चे नाव, मेथड्स्, फंक्शन्स्, वेरियेबल नावे व रिटअर्न मूल्य <code class="literal">मोनो-स्पेस्ड् बोल्ड</code> मध्ये प्रस्तूत केले जातील. उदाहरणार्थ:
</div><div class="blockquote"><blockquote class="blockquote"><div class="para">
फाइल-संबंधित वर्ग अंतर्गत फाइल प्रणाली करीता <code class="classname">filesystem</code>, फाइल करीता <code class="classname">file</code>, व संचयीका करीता <code class="classname">dir</code> समाविष्टीत आहे. प्रत्येक वर्गकाकडे संबंधित परवानगी संच समाविष्ठीत आहे.
</div></blockquote></div><div class="para">
<span class="application"><strong>प्रप्रोर्श्नल बोल्ड</strong></span>
</div><div class="para">
हे प्रणालीवरील शब्द किंवा वाक्यरचना दाखवते, ज्यामध्ये ऍनीमेशनचे नाव; संवादपेटीतील मजकूर; लेबल बटने; चेक-बॉक्स् व रेडिओ बटन लेबल्स्; मेन्यू शिर्षक व उप-मेन्यू शिर्षकाचे समावेश आहे. उदाहरणार्थ:
</div><div class="blockquote"><blockquote class="blockquote"><div class="para">
<span class="guimenu"><strong>प्रणाली</strong></span> → <span class="guisubmenu"><strong>पसंती</strong></span> → <span class="guimenuitem"><strong>माऊस</strong></span> पर्याय मुख्य मेन्यू पट्टीतून नीवडा व <span class="application"><strong>माऊस पसंती</strong></span> सुरू करा. <span class="guilabel"><strong>बटन्स्</strong></span> टॅबमध्ये, <span class="guilabel"><strong>डावे-हाताळणी माऊस</strong></span> चेक बॉक्स क्लिक करा व <span class="guibutton"><strong>बंद करा</strong></span> क्लिक करून प्राथमीक माऊस बटन डावीपासून ऊजवीकडे बदला (यामुले उजव्या हाताळणीच्या वापरकर्त्यांना माऊस हाताळणी सोपे होते).
</div><div class="para">
<span class="application"><strong>gedit</strong></span> फाइलमध्ये विशेष अक्षर अंतर्भूत करण्यासाठी, मुख्य मेन्यू पट्टीतून <span class="guimenu"><strong>ऍप्लिकेशन्स्</strong></span> → <span class="guisubmenu"><strong>ऍक्सेसरीज्</strong></span> → <span class="guimenuitem"><strong>अक्षर मॅप</strong></span> नीवडा. पुढे, <span class="guimenu"><strong>शोधा</strong></span> → <span class="guimenuitem"><strong>शोधा…</strong></span> नीवडा, <span class="application"><strong>अक्षर मॅप</strong></span> मेन्यू पट्टीतून, अक्षराचे नाव <span class="guilabel"><strong>शोधा</strong></span> क्षेत्रात टाईप करा व <span class="guibutton"><strong>पुढचे</strong></span>बटन क्लिक करा. शोधकरण्याजोगी अक्षर <span class="guilabel"><strong>अक्षर तक्ता</strong></span> येथे ठळक केले जाईल. हे ठळक केलेले अक्षराला दोनवेळा क्लिक केल्यानंतर <span class="guilabel"><strong>प्रत बनवण्याजोगी मजकूर</strong></span> क्षेत्रात स्थीत करा व <span class="guibutton"><strong>प्रत बनवा</strong></span> बटनावर क्लिक करा. आत्ता दस्तऐवजाकडे जा व <span class="guimenu"><strong>संपादीत करा</strong></span> → <span class="guimenuitem"><strong>चिकटवा</strong></span> पर्याय <span class="application"><strong>gedit</strong></span> मेन्यू पट्टीतून नीवडा.
</div></blockquote></div><div class="para">
वरील मजकूरमध्ये ऍप्लिकेशनचे नावे; प्रणाली-क्षेत्र मेन्यू नावे व घटके; ऍप्लिकेशन्स्-निर्देशीत मेन्यू नावे; व बटने व GUI संवादमधील मजकूर समाविष्टीत आहे, सर्व प्रप्रोर्श्नल बोल्डमध्ये प्रस्तुत केले आहेत व संदर्भशी नीगडीत आहे.
</div><div class="para">
<code class="command"><em class="replaceable"><code>मोनो-स्पेस्ड् बोल्ड इटॅलीक</code></em></code> किंवा <span class="application"><strong><em class="replaceable"><code>प्रप्रोर्श्नल बोल्ड इटॅलीक</code></em></strong></span>
</div><div class="para">
मोनो-स्पेस्ड् बोल्ड किंवा प्रप्रोर्श्नल बोल्ड, इटॅलीक्स् बदलविण्याजोगी किंवा बदलाव पाठ्य दर्शविते. इटॅलीक्स् तुम्ही इच्छिकरित्या प्रविष्ट न केलेलेकिंवा परस्पर स्थिती नुरूप बदलणारे पाठ्य दर्शविते. उदाहरणार्थ:
</div><div class="blockquote"><blockquote class="blockquote"><div class="para">
दूर्रस्थ मशीनशी ssh द्वारे जुळवणी स्थापीत करायचे असल्यास, शेल प्रॉम्पटवर <code class="command">ssh <em class="replaceable"><code>वापरकर्तानाव</code></em>@<em class="replaceable"><code>क्षेत्र.नाव</code></em></code> टाइप करा. दूर्रस्थ मशीन <code class="filename">example.com</code> असल्यास व वापरकर्त्याचे नाव john असल्यास, <code class="command">ssh john@example.com</code> टाइप करा.
</div><div class="para">
<code class="command">mount -o remount <em class="replaceable"><code>फाइल-प्रणली</code></em></code> आदेश, नामांकीत फाइल प्रणालीस पुन्ह आरोहीत करते. उदाहरणार्थ, <code class="filename">/home</code> फाइल प्रणाली पुन्हा आरोहीत करण्याकरीत, <code class="command">mount -o remount /home</code> असे आदेश आहे.
</div><div class="para">
वर्तमानरित्या प्रतिष्ठापीत संकुलाची आवृत्ती पहाची असल्यावर, <code class="command">rpm -q <em class="replaceable"><code>संकुल</code></em></code> आदेश वापरा. परिणाम खालिल नुरूप दर्शविले जातील: <code class="command"><em class="replaceable"><code>संकुल-आवृत्ती-प्रकाशन</code></em></code>.
</div></blockquote></div><div class="para">
वरील ठळकइटॅलीक् नुरूप शब्द जसे की — वापरकर्तानाव, क्षेत्र.नाव, फाइल-प्रणाली, संकुल, आवृत्ती व प्रकाशन यांस स्मर्णास ठेवा. आदेश प्रविष्ट करतेवेळीचे पाठ्य करीताकिंवा प्रणाली द्वारे दर्शविलेले पाठ्य करीता, प्रत्येक शब्द हा प्लेसहोल्डर आहे.
</div><div class="para">
कार्य शिर्षक करीता मानक वापर याच्या व्यतिरिक्त, इटॅलीक्स्चा वापरप्रथम किंवा महत्वाची संज्ञा दर्शविण्याकरीता केला जातो. उदाहरणार्थ:
</div><div class="blockquote"><blockquote class="blockquote"><div class="para">
पब्लिकन <em class="firstterm">डॉकबूक</em> प्रकाशन प्रणाली आहे.
</div></blockquote></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title" id="id563161">3.2. पूल्ल-कोट् नियमावली</h3></div></div></div><div class="para">
भोवतालच्या मजकूर पासून टर्मिनलचे आऊटपुट व स्रोत कोड सूची दृष्यास्पदपणे सेट केले जाते.
</div><div class="para">
टर्मिनलकरीता पाठवलेले आऊटपुट <code class="computeroutput">मोनो-स्पेस्ड् रोमन</code> मध्ये निश्चित केले असते व याप्रमाणे प्रस्तुत केले जाते:
</div><pre class="screen">books Desktop documentation drafts mss photos stuff svn
books_tests Desktop1 downloads images notes scripts svgs</pre><div class="para">
सोअर्स-कोड सूची देखील <code class="computeroutput">मोनो-स्पेस्ड् रोमन</code> मध्ये सेट केले जाते परंतु रचना या प्रकारे ठळक केली जाते:
</div><pre class="programlisting">package org.<span class="perl_Function">jboss</span>.<span class="perl_Function">book</span>.<span class="perl_Function">jca</span>.<span class="perl_Function">ex1</span>;
<span class="perl_Keyword">import</span> javax.naming.InitialContext;
<span class="perl_Keyword">public</span> <span class="perl_Keyword">class</span> ExClient
{
<span class="perl_Keyword">public</span> <span class="perl_DataType">static</span> <span class="perl_DataType">void</span> <span class="perl_Function">main</span>(String args[])
<span class="perl_Keyword">throws</span> Exception
{
InitialContext iniCtx = <span class="perl_Keyword">new</span> InitialContext();
Object ref = iniCtx.<span class="perl_Function">lookup</span>(<span class="perl_String">"EchoBean"</span>);
EchoHome home = (EchoHome) ref;
Echo echo = home.<span class="perl_Function">create</span>();
System.<span class="perl_Function">out</span>.<span class="perl_Function">println</span>(<span class="perl_String">"Created Echo"</span>);
System.<span class="perl_Function">out</span>.<span class="perl_Function">println</span>(<span class="perl_String">"Echo.echo('Hello') = "</span> + echo.<span class="perl_Function">echo</span>(<span class="perl_String">"Hello"</span>));
}
}</pre></div><div class="section"><div class="titlepage"><div><div><h3 class="title" id="id563272">3.3. टिप व सावधानता</h3></div></div></div><div class="para">
शेवटी, दुर्लक्ष करण्याजोगी माहितीकडे लक्ष वेधण्याकरीता तीन दृश्यास्पद शैली वापरली जाते.
</div><div class="note"><div class="admonition_header"><h2>टिप्पणी</h2></div><div class="admonition"><div class="para">
टिपण्णी सहसा टिपा, शार्टकट्स् किंवा ठराविक कार्यसाठी वैकल्पिक पर्याय आहे. टिपांकडे दुर्लक्ष केल्यास नकारात्मक परिणाम आढळत नाही, परंतु बरेच सोप्या गोष्टी तुम्ही गमवाल.
</div></div></div><div class="important"><div class="admonition_header"><h2>महत्वाचे</h2></div><div class="admonition"><div class="para">
महत्वाच्या बॉक्सेजमध्ये सहज न आढळणाऱ्या बाबचे समावेश आहे: संरचना बदल जे फक्त सध्याच्या सत्रकरीता लागू होतात, किंवा सेवा ज्यांस सुधारणापूर्वी पुनः सुरू करणे आवश्यक आहे लागू केले जातात. 'महत्वाचे' असे लेबल केलेल्या बॉक्सकडे दुर्लक्ष केल्यास डाटा नाहीसा होत नाही परंतु त्रास नक्की होतो.
</div></div></div><div class="warning"><div class="admonition_header"><h2>सावधानता</h2></div><div class="admonition"><div class="para">
सावधानता दुर्लक्ष करू नका. सावधानताकडे दुर्लक्ष केल्यास माहिती लुप्त होऊ शकते.
</div></div></div></div></div><div class="section" id="s1-intro-feedback-GFS"><div class="titlepage"><div><div><h2 class="title" id="s1-intro-feedback-GFS">4. Feedback</h2></div></div></div><a id="id563399" class="indexterm"></a><a id="id563043" class="indexterm"></a><div class="para">
If you spot a typo, or if you have thought of a way to make this manual better, we would love to hear from you. Please submit a report in Bugzilla (<a href="http://bugzilla.redhat.com/bugzilla/">http://bugzilla.redhat.com/bugzilla/</a>) against the component <span class="guimenuitem"><strong>Documentation-cluster</strong></span>.
</div><div class="para">
Be sure to mention the manual's identifier:
</div><pre class="screen">
Bugzilla component: Documentation-cluster
Book identifier: Global_File_System(EN)-5 (2012-1-24T15:10)
</pre><div class="para">
By mentioning this manual's identifier, we know exactly which version of the guide you have.
</div><div class="para">
If you have a suggestion for improving the documentation, try to be as specific as possible. If you have found an error, please include the section number and some of the surrounding text so we can find it easily.
</div></div></div><div xml:lang="mr-IN" class="chapter" id="ch-overview-GFS" lang="mr-IN"><div class="titlepage"><div><div><h2 class="title">धडा 1. GFS Overview</h2></div></div></div><div class="toc"><dl><dt><span class="section"><a href="#s1-ov-newfeatures-GFS">1.1. New and Changed Features</a></span></dt><dt><span class="section"><a href="#s1-ov-perform-GFS">1.2. Performance, Scalability, and Economy</a></span></dt><dd><dl><dt><span class="section"><a href="#s2-ov-superior-GFS">1.2.1. Superior Performance and Scalability</a></span></dt><dt><span class="section"><a href="#s2-ov-economy-GFS">1.2.2. Economy and Performance</a></span></dt></dl></dd><dt><span class="section"><a href="#s1-ov-subsystems-GFS">1.3. GFS Software Components</a></span></dt><dt><span class="section"><a href="#s1-ov-preconfig-GFS">1.4. Before Setting Up GFS</a></span></dt></dl></div><a id="id685121" class="indexterm"></a><div class="para">
The Red Hat GFS file system is a native file system that interfaces directly with the Linux kernel file system interface (VFS layer). When implemented as a cluster file system, GFS employs distributed metadata and multiple journals. Red Hat supports the use of GFS file systems only as implemented in Red Hat Cluster Suite.
</div><div class="note"><div class="admonition_header"><h2>टीप</h2></div><div class="admonition"><div class="para">
Although a GFS file system can be implemented in a standalone system or as part of a cluster configuration, for the Red Hat Enterprise Linux 5.5 release and later Red Hat does not support the use of GFS as a single-node file system. Red Hat does support a number of high-performance single node file systems which are optimized for single node and thus have generally lower overhead than a cluster filesystem. Red Hat recommends using these file systems in preference to GFS in cases where only a single node needs to mount the file system.
</div><div class="para">
Red Hat will continue to support single-node GFS file systems for existing customers.
</div></div></div><div class="note"><div class="admonition_header"><h2>टीप</h2></div><div class="admonition"><div class="para">
Red Hat does not support using GFS for cluster file system deployments greater than 16 nodes.
</div></div></div><div class="para">
GFS is based on a 64-bit architecture, which can theoretically accommodate an 8 EB file system. However, the current supported maximum size of a GFS file system for 64-bit hardware is 100 TB. The current supported maximum size of a GFS file system for 32-bit hardware is 16 TB. If your system requires larger GFS file systems, contact your Red Hat service representative.
</div><a id="id675825" class="indexterm"></a><a id="id564922" class="indexterm"></a><div class="para">
When determining the size of your file system, you should consider your recovery needs. Running the <code class="command">gfs_fsck</code> command on a very large file system can take a long time and consume a large amount of memory. Additionally, in the event of a disk or disk-subsytem failure, recovery time is limited by the speed of your backup media. For information on the amount of memory the <code class="command">gfs_fsck</code> command requires, see <a class="xref" href="#s1-manage-repairfs">विभाग 3.14, “Repairing a File System”</a>.
</div><div class="para">
When configured in a Red Hat Cluster Suite, Red Hat GFS nodes can be configured and managed with Red Hat Cluster Suite configuration and management tools. Red Hat GFS then provides data sharing among GFS nodes in a Red Hat cluster, with a single, consistent view of the file system name space across the GFS nodes. This allows processes on different nodes to share GFS files in the same way that processes on the same node can share files on a local file system, with no discernible difference. For information about Red Hat Cluster Suite refer to <em class="citetitle">Configuring and Managing a Red Hat Cluster</em>.
</div><div class="para">
While a GFS file system may be used outside of LVM, Red Hat supports only GFS file systems that are created on a CLVM logical volume. CLVM is a cluster-wide implementation of LVM, enabled by the CLVM daemon <code class="command">clvmd</code>, which manages LVM logical volumes in a Red Hat Cluster Suite cluster. The daemon makes it possible to use LVM2 to manage logical volumes across a cluster, allowing all nodes in the cluster to share the logical volumes. For information on the LVM volume manager, see <em class="citetitle">Logical Volume Manager Administration</em>
</div><div class="note"><div class="admonition_header"><h2>Note</h2></div><div class="admonition"><div class="para">
When you configure a GFS file system as a cluster file system, you must ensure that all nodes in the cluster have access to the shared file system. Asymmetric cluster configurations in which some nodes have access to the file system and others do not are not supported.
</div></div></div><div class="para">
This chapter provides some basic, abbreviated information as background to help you understand GFS. It contains the following sections:
</div><div class="itemizedlist"><ul><li class="listitem"><div class="para">
<a class="xref" href="#s1-ov-newfeatures-GFS">विभाग 1.1, “New and Changed Features”</a>
</div></li><li class="listitem"><div class="para">
<a class="xref" href="#s1-ov-perform-GFS">विभाग 1.2, “Performance, Scalability, and Economy”</a>
</div></li><li class="listitem"><div class="para">
<a class="xref" href="#s1-ov-subsystems-GFS">विभाग 1.3, “GFS Software Components”</a>
</div></li><li class="listitem"><div class="para">
<a class="xref" href="#s1-ov-preconfig-GFS">विभाग 1.4, “Before Setting Up GFS”</a>
</div></li></ul></div><div class="section" id="s1-ov-newfeatures-GFS"><div class="titlepage"><div><div><h2 class="title" id="s1-ov-newfeatures-GFS">1.1. New and Changed Features</h2></div></div></div><a id="id391918" class="indexterm"></a><a id="id391930" class="indexterm"></a><a id="id391938" class="indexterm"></a><a id="id391945" class="indexterm"></a><div class="para">
This section lists new and changed features included with the initial release of Red Hat Enterprise Linux 5.
</div><div class="itemizedlist"><ul><li class="listitem"><div class="para">
GULM (Grand Unified Lock Manager) is not supported in Red Hat Enterprise Linux 5. If your GFS file systems use the GULM lock manager, you must convert the file systems to use the DLM lock manager. This is a two-part process.
</div><div class="itemizedlist"><ul><li class="listitem"><div class="para">
While running Red Hat Enterprise Linux 4, convert your GFS file systems to use the DLM lock manager.
</div></li><li class="listitem"><div class="para">
Upgrade your operating system to Red Hat Enterprise Linux 5, converting the lock manager to DLM when you do.
</div></li></ul></div><div class="para">
For information on upgrading to Red Hat Enterprise Linux 5 and converting GFS file systems to use the DLM lock manager, see <span class="emphasis"><em>Configuring and Managing a Red Hat Cluster.</em></span>
</div></li><li class="listitem"><div class="para">
Documentation for Red Hat Cluster Suite for Red Hat Enterprise Linux 5 has been expanded and reorganized. For information on the available documents, see <a class="xref" href="#Related_Documentation-GFS">विभाग 2, “Related Documentation”</a>.
</div></li></ul></div></div><div class="section" id="s1-ov-perform-GFS"><div class="titlepage"><div><div><h2 class="title" id="s1-ov-perform-GFS">1.2. Performance, Scalability, and Economy</h2></div></div></div><a id="id384144" class="indexterm"></a><a id="id384156" class="indexterm"></a><a id="id341336" class="indexterm"></a><div class="para">
You can deploy GFS in a variety of configurations to suit your needs for performance, scalability, and economy. For superior performance and scalability, you can deploy GFS in a cluster that is connected directly to a SAN. For more economical needs, you can deploy GFS in a cluster that is connected to a LAN with servers that use <em class="firstterm">GNBD</em> (Global Network Block Device).
</div><div class="para">
The following sections provide examples of how GFS can be deployed to suit your needs for performance, scalability, and economy:
</div><div class="itemizedlist"><ul><li class="listitem"><div class="para">
<a class="xref" href="#s2-ov-superior-GFS">विभाग 1.2.1, “Superior Performance and Scalability”</a>
</div></li><li class="listitem"><div class="para">
<a class="xref" href="#s2-ov-economy-GFS">विभाग 1.2.2, “Economy and Performance”</a>
</div></li></ul></div><div class="note"><div class="admonition_header"><h2>Note</h2></div><div class="admonition"><div class="para">
The deployment examples in this chapter reflect basic configurations; your needs might require a combination of configurations shown in the examples.
</div></div></div><div class="section" id="s2-ov-superior-GFS"><div class="titlepage"><div><div><h3 class="title" id="s2-ov-superior-GFS">1.2.1. Superior Performance and Scalability</h3></div></div></div><div class="para">
You can obtain the highest shared-file performance when applications access storage directly. The GFS SAN configuration in <a class="xref" href="#fig-gfs-with-san">आकृती 1.1, “GFS with a SAN”</a> provides superior file performance for shared files and file systems. Linux applications run directly on GFS nodes. Without file protocols or storage servers to slow data access, performance is similar to individual Linux servers with directly connected storage; yet, each GFS application node has equal access to all data files. GFS supports up to 125 GFS nodes.
</div><div class="figure" id="fig-gfs-with-san"><div class="figure-contents"><div class="mediaobject"><img src="./images/overview/fig-gfs-with-san.png" alt="GFS with a SAN" /><div class="longdesc"><div class="para">
GFS with a SAN
</div></div></div></div><h6>आकृती 1.1. GFS with a SAN</h6></div><br class="figure-break" /></div><div class="section" id="s2-ov-economy-GFS"><div class="titlepage"><div><div><h3 class="title" id="s2-ov-economy-GFS">1.2.2. Economy and Performance</h3></div></div></div><div class="para">
Multiple Linux client applications on a LAN can share the same SAN-based data as shown in <a class="xref" href="#fig-gfs-gnbd-san">आकृती 1.2, “GFS and GNBD with a SAN”</a>. SAN block storage is presented to network clients as block storage devices by GNBD servers. From the perspective of a client application, storage is accessed as if it were directly attached to the server in which the application is running. Stored data is actually on the SAN. Storage devices and data can be equally shared by network client applications. File locking and sharing functions are handled by GFS for each network client.
</div><div class="note"><div class="admonition_header"><h2>Note</h2></div><div class="admonition"><div class="para">
Clients implementing ext2 and ext3 file systems can be configured to access their own dedicated slice of SAN storage.
</div></div></div><div class="figure" id="fig-gfs-gnbd-san"><div class="figure-contents"><div class="mediaobject"><img src="./images/overview/fig-gfs-gnbd-san.png" alt="GFS and GNBD with a SAN" /><div class="longdesc"><div class="para">
GFS and GNBD with a SAN
</div></div></div></div><h6>आकृती 1.2. GFS and GNBD with a SAN</h6></div><br class="figure-break" /><div class="para">
<a class="xref" href="#fig-gfs-gnbd-storage">आकृती 1.3, “GFS and GNBD with Directly Connected Storage”</a> shows how Linux client applications can take advantage of an existing Ethernet topology to gain shared access to all block storage devices. Client data files and file systems can be shared with GFS on each client. Application failover can be fully automated with Red Hat Cluster Suite.
</div><div class="figure" id="fig-gfs-gnbd-storage"><div class="figure-contents"><div class="mediaobject"><img src="./images/overview/fig-gfs-gnbd-storage.png" alt="GFS and GNBD with Directly Connected Storage" /><div class="longdesc"><div class="para">
GFS and GNBD with Direct-Attached Storage
</div></div></div></div><h6>आकृती 1.3. GFS and GNBD with Directly Connected Storage</h6></div><br class="figure-break" /></div></div><div class="section" id="s1-ov-subsystems-GFS"><div class="titlepage"><div><div><h2 class="title" id="s1-ov-subsystems-GFS">1.3. GFS Software Components</h2></div></div></div><a id="id402739" class="indexterm"></a><a id="id402751" class="indexterm"></a><div class="para">
<a class="xref" href="#tb-table-ov-gfs-subsys">तक्ता 1.1, “GFS Software Subsystem Components”</a> summarizes the GFS software components.
</div><a id="id402767" class="indexterm"></a><a id="id402779" class="indexterm"></a><div class="table" id="tb-table-ov-gfs-subsys"><h6>तक्ता 1.1. GFS Software Subsystem Components</h6><div class="table-contents"><table summary="GFS Software Subsystem Components" border="1"><colgroup><col width="38%" class="Subsystem" /><col width="63%" class="Description" /></colgroup><thead><tr><th>
Software Component
</th><th>
Description
</th></tr></thead><tbody><tr><td>
<code class="command">gfs.ko</code>
</td><td>
Kernel module that implements the GFS file system and is loaded on GFS cluster nodes.
</td></tr><tr><td>
<code class="command">lock_dlm.ko</code>
</td><td>
A lock module that implements DLM locking for GFS. It plugs into the lock harness, <code class="command">lock_harness.ko</code> and communicates with the DLM lock manager in Red Hat Cluster Suite.
</td></tr><tr><td>
<code class="command">lock_nolock.ko</code>
</td><td>
A lock module for use when GFS is used as a local file system only. It plugs into the lock harness, <code class="command">lock_harness.ko</code> and provides local locking.
</td></tr></tbody></table></div></div><br class="table-break" /></div><div class="section" id="s1-ov-preconfig-GFS"><div class="titlepage"><div><div><h2 class="title" id="s1-ov-preconfig-GFS">1.4. Before Setting Up GFS</h2></div></div></div><a id="id524979" class="indexterm"></a><a id="id524991" class="indexterm"></a><div class="para">
Before you install and set up GFS, note the following key characteristics of your GFS file systems:
</div><div class="variablelist"><dl><dt class="varlistentry"><span class="term">GFS nodes</span></dt><dd><div class="para">
Determine which nodes in the Red Hat Cluster Suite will mount the GFS file systems.
</div></dd><dt class="varlistentry"><span class="term">Number of file systems</span></dt><dd><div class="para">
Determine how many GFS file systems to create initially. (More file systems can be added later.)
</div></dd><dt class="varlistentry"><span class="term">File system name</span></dt><dd><div class="para">
Determine a unique name for each file system. Each file system name is required in the form of a parameter variable. For example, this book uses file system names <code class="option">mydata1</code> and <code class="option">mydata2</code> in some example procedures.
</div></dd><dt class="varlistentry"><span class="term">File system size</span></dt><dd><div class="para">
GFS is based on a 64-bit architecture, which can theoretically accommodate an 8 EB file system. However, the current supported maximum size of a GFS file system for 64-bit hardware is 100 TB. The current supported maximum size of a GFS file system for 32-bit hardware is 16 TB. If your system requires larger GFS file systems, contact your Red Hat service representative.
</div><a id="id525080" class="indexterm"></a><a id="id525088" class="indexterm"></a><div class="para">
When determining the size of your file system, you should consider your recovery needs. Running the <code class="command">gfs_fsck</code> command on a very large file system can take a long time and consume a large amount of memory. Additionally, in the event of a disk or disk-subsytem failure, recovery time is limited by the speed of your backup media. For information on the amount of memory the <code class="command">gfs_fsck</code> command requires, see <a class="xref" href="#s1-manage-repairfs">विभाग 3.14, “Repairing a File System”</a>.
</div></dd><dt class="varlistentry"><span class="term">Journals</span></dt><dd><div class="para">
Determine the number of journals for your GFS file systems. One journal is required for each node that mounts a GFS file system. Make sure to account for additional journals needed for future expansion, as you cannot add journals dynamically to a GFS file system.
</div></dd><dt class="varlistentry"><span class="term">GNBD server nodes</span></dt><dd><div class="para">
If you are using GNBD, determine how many GNBD server nodes are needed. Note the hostname and IP address of each GNBD server node for setting up GNBD clients later. For information on using GNBD with GFS, see the <span class="emphasis"><em>Using GNBD with Global File System</em></span> document.
</div></dd><dt class="varlistentry"><span class="term">Storage devices and partitions</span></dt><dd><div class="para">
Determine the storage devices and partitions to be used for creating logical volumes (via CLVM) in the file systems.
</div></dd></dl></div><div class="note"><div class="admonition_header"><h2>Note</h2></div><div class="admonition"><div class="para">
You may see performance problems with GFS when many create and delete operations are issued from more than one node in the same directory at the same time. If this causes performance problems in your system, you should localize file creation and deletions by a node to directories specific to that node as much as possible.
</div></div></div></div></div><div xml:lang="mr-IN" class="chapter" id="ch-config" lang="mr-IN"><div class="titlepage"><div><div><h2 class="title">धडा 2. Getting Started</h2></div></div></div><div class="toc"><dl><dt><span class="section"><a href="#s1-config-prereq">2.1. Prerequisite Tasks</a></span></dt><dt><span class="section"><a href="#s1-config-tasks">2.2. Initial Setup Tasks</a></span></dt></dl></div><a id="id583292" class="indexterm"></a><div class="para">
This chapter describes procedures for initial setup of GFS and contains the following sections:
</div><div class="itemizedlist"><ul><li class="listitem"><div class="para">
<a class="xref" href="#s1-config-prereq">विभाग 2.1, “Prerequisite Tasks”</a>
</div></li><li class="listitem"><div class="para">
<a class="xref" href="#s1-config-tasks">विभाग 2.2, “Initial Setup Tasks”</a>
</div></li></ul></div><div class="section" id="s1-config-prereq"><div class="titlepage"><div><div><h2 class="title" id="s1-config-prereq">2.1. Prerequisite Tasks</h2></div></div></div><a id="id614023" class="indexterm"></a><a id="id564127" class="indexterm"></a><div class="para">
You should complete the following tasks before setting up Red Hat GFS:
</div><div class="itemizedlist"><ul><li class="listitem"><div class="para">
Make sure that you have noted the key characteristics of the GFS nodes (refer to <a class="xref" href="#s1-ov-preconfig-GFS">विभाग 1.4, “Before Setting Up GFS”</a>).
</div></li><li class="listitem"><div class="para">
Make sure that the clocks on the GFS nodes are synchronized. It is recommended that you use the Network Time Protocol (NTP) software provided with your Red Hat Enterprise Linux distribution.
</div><div class="note"><div class="admonition_header"><h2>Note</h2></div><div class="admonition"><div class="para">
The system clocks in GFS nodes must be within a few minutes of each other to prevent unnecessary inode time-stamp updating. Unnecessary inode time-stamp updating severely impacts cluster performance.
</div></div></div></li><li class="listitem"><div class="para">
In order to use GFS in a clustered environment, you must configure your system to use the Clustered Logical Volume Manager (CLVM), a set of clustering extensions to the LVM Logical Volume Manager. In order to use CLVM, the Red Hat Cluster Suite software, including the <code class="command">clvmd</code> daemon, must be running. For information on using CLVM, see <em class="citetitle">Logical Volume Manager Administration</em>. For information on installing and administering Red Hat Cluster Suite, see <em class="citetitle">Cluster Administration</em>.
</div></li></ul></div></div><div class="section" id="s1-config-tasks"><div class="titlepage"><div><div><h2 class="title" id="s1-config-tasks">2.2. Initial Setup Tasks</h2></div></div></div><a id="id528468" class="indexterm"></a><a id="id603860" class="indexterm"></a><div class="para">
Initial GFS setup consists of the following tasks:
</div><div class="orderedlist"><ol><li class="listitem"><div class="para">
Setting up logical volumes
</div></li><li class="listitem"><div class="para">
Making a GFS files system
</div></li><li class="listitem"><div class="para">
Mounting file systems
</div></li></ol></div><div class="para">
Follow these steps to set up GFS initially.
</div><div class="orderedlist"><ol><li class="listitem"><div class="para">
Using LVM, create a logical volume for each Red Hat GFS file system.
</div><div class="note"><div class="admonition_header"><h2>Note</h2></div><div class="admonition"><div class="para">
You can use <code class="filename">init.d</code> scripts included with Red Hat Cluster Suite to automate activating and deactivating logical volumes. For more information about <code class="filename">init.d</code> scripts, refer to <span class="emphasis"><em>Configuring and Managing a Red Hat Cluster</em></span>.
</div></div></div></li><li class="listitem"><div class="para">
Create GFS file systems on logical volumes created in Step 1. Choose a unique name for each file system. For more information about creating a GFS file system, refer to <a class="xref" href="#s1-manage-makefs">विभाग 3.1, “Creating a File System”</a>.
</div><div class="para">
You can use either of the following formats to create a clustered GFS file system:
</div><pre class="screen">
gfs_mkfs -p lock_dlm -t <em class="parameter"><code>ClusterName:FSName</code></em> -j <em class="parameter"><code>NumberJournals BlockDevice</code></em></pre><pre class="screen">
mkfs -t gfs -p lock_dlm -t <em class="parameter"><code>LockTableName</code></em> -j <em class="parameter"><code>NumberJournals BlockDevice</code></em></pre><div class="para">
You can use either of the following formats to create a local GFS file system:
</div><pre class="screen">
gfs_mkfs -p lock_nolock -j <em class="parameter"><code>NumberJournals BlockDevice</code></em></pre><pre class="screen">
mkfs -t gfs -p lock_nolock -j <em class="parameter"><code>NumberJournals BlockDevice</code></em></pre><div class="para">
For more information on creating a GFS file system, see <a class="xref" href="#s1-manage-makefs">विभाग 3.1, “Creating a File System”</a>.
</div></li><li class="listitem"><div class="para">
At each node, mount the GFS file systems. For more information about mounting a GFS file system, see <a class="xref" href="#s1-manage-mountfs">विभाग 3.2, “Mounting a File System”</a>.
</div><div class="para">
Command usage:
</div><div class="para">
<code class="command">mount <em class="replaceable"><code>BlockDevice MountPoint</code></em></code>
</div><div class="para">
<code class="command">mount -o acl <em class="replaceable"><code>BlockDevice MountPoint</code></em></code>
</div><div class="para">
The <code class="command"><code class="option">-o</code> acl</code> mount option allows manipulating file ACLs. If a file system is mounted without the <code class="command"><code class="option">-o</code> acl</code> mount option, users are allowed to view ACLs (with <code class="command">getfacl</code>), but are not allowed to set them (with <code class="command">setfacl</code>).
</div><div class="note"><div class="admonition_header"><h2>Note</h2></div><div class="admonition"><div class="para">
You can use <code class="filename">init.d</code> scripts included with Red Hat Cluster Suite to automate mounting and unmounting GFS file systems. For more information about <code class="filename">init.d</code> scripts, refer to <span class="emphasis"><em>Configuring and Managing a Red Hat Cluster</em></span>.
</div></div></div></li></ol></div></div></div><div xml:lang="mr-IN" class="chapter" id="ch-manage" lang="mr-IN"><div class="titlepage"><div><div><h2 class="title">धडा 3. Managing GFS</h2></div></div></div><div class="toc"><dl><dt><span class="section"><a href="#s1-manage-makefs">3.1. Creating a File System</a></span></dt><dt><span class="section"><a href="#s1-manage-mountfs">3.2. Mounting a File System</a></span></dt><dt><span class="section"><a href="#s1-manage-unmountfs">3.3. Unmounting a File System</a></span></dt><dt><span class="section"><a href="#s1-mount-considerations">3.4. Special Considerations when Mounting GFS File Systems</a></span></dt><dt><span class="section"><a href="#s1-manage-tunables">3.5. Displaying GFS Tunable Parameters</a></span></dt><dt><span class="section"><a href="#s1-manage-quota">3.6. GFS Quota Management</a></span></dt><dd><dl><dt><span class="section"><a href="#s2-manage-setquota">3.6.1. Setting Quotas</a></span></dt><dt><span class="section"><a href="#s2-manage-displayquota">3.6.2. Displaying Quota Limits and Usage</a></span></dt><dt><span class="section"><a href="#s2-manage-synchquota">3.6.3. Synchronizing Quotas</a></span></dt><dt><span class="section"><a href="#s2-manage-enablequota">3.6.4. Disabling/Enabling Quota Enforcement</a></span></dt><dt><span class="section"><a href="#s2-manage-quotaaccount">3.6.5. Disabling/Enabling Quota Accounting</a></span></dt></dl></dd><dt><span class="section"><a href="#s1-manage-growfs">3.7. Growing a File System</a></span></dt><dt><span class="section"><a href="#s1-manage-addjournalfs">3.8. Adding Journals to a File System</a></span></dt><dt><span class="section"><a href="#s1-manage-direct-io">3.9. Direct I/O</a></span></dt><dd><dl><dt><span class="section"><a href="#s2-manage-odirect">3.9.1. <code class="option">O_DIRECT</code></a></span></dt><dt><span class="section"><a href="#s2-manage-fileattribute">3.9.2. GFS File Attribute</a></span></dt><dt><span class="section"><a href="#s2-manage-dirattribute">3.9.3. GFS Directory Attribute</a></span></dt></dl></dd><dt><span class="section"><a href="#s1-manage-data-journal">3.10. Data Journaling</a></span></dt><dt><span class="section"><a href="#s1-manage-atimeconf">3.11. Configuring <code class="command">atime</code> Updates</a></span></dt><dd><dl><dt><span class="section"><a href="#s2-manage-mountnoatime">3.11.1. Mount with <code class="command">noatime</code></a></span></dt><dt><span class="section"><a href="#s2-manage-tuneatime">3.11.2. Tune GFS <code class="command">atime</code> Quantum</a></span></dt></dl></dd><dt><span class="section"><a href="#s1-manage-suspendfs">3.12. Suspending Activity on a File System</a></span></dt><dt><span class="section"><a href="#s1-manage-displaystats">3.13. Displaying Extended GFS Information and Statistics</a></span></dt><dd><dl><dt><span class="section"><a href="#s2-manage-displayspace">3.13.1. Displaying GFS Space Usage</a></span></dt><dt><span class="section"><a href="#s1-manage-displaycounts">3.13.2. Displaying GFS Counters</a></span></dt><dt><span class="section"><a href="#s1-manage-displayexstat">3.13.3. Displaying Extended Status</a></span></dt></dl></dd><dt><span class="section"><a href="#s1-manage-repairfs">3.14. Repairing a File System</a></span></dt><dt><span class="section"><a href="#s1-manage-pathnames">3.15. Context-Dependent Path Names</a></span></dt><dt><span class="section"><a href="#s1-manage-gfswithdraw">3.16. The GFS Withdraw Function</a></span></dt></dl></div><a id="id563214" class="indexterm"></a><a id="id600332" class="indexterm"></a><div class="para">
This chapter describes the tasks and commands for managing GFS and consists of the following sections:
</div><div class="itemizedlist"><ul><li class="listitem"><div class="para">
<a class="xref" href="#s1-manage-makefs">विभाग 3.1, “Creating a File System”</a>
</div></li><li class="listitem"><div class="para">
<a class="xref" href="#s1-manage-mountfs">विभाग 3.2, “Mounting a File System”</a>
</div></li><li class="listitem"><div class="para">
<a class="xref" href="#s1-manage-unmountfs">विभाग 3.3, “Unmounting a File System”</a>
</div></li><li class="listitem"><div class="para">
<a class="xref" href="#s1-mount-considerations">विभाग 3.4, “Special Considerations when Mounting GFS File Systems”</a>
</div></li><li class="listitem"><div class="para">
<a class="xref" href="#s1-manage-tunables">विभाग 3.5, “Displaying GFS Tunable Parameters”</a>
</div></li><li class="listitem"><div class="para">
<a class="xref" href="#s1-manage-quota">विभाग 3.6, “GFS Quota Management”</a>
</div></li><li class="listitem"><div class="para">
<a class="xref" href="#s1-manage-growfs">विभाग 3.7, “Growing a File System”</a>
</div></li><li class="listitem"><div class="para">
<a class="xref" href="#s1-manage-addjournalfs">विभाग 3.8, “Adding Journals to a File System”</a>
</div></li><li class="listitem"><div class="para">
<a class="xref" href="#s1-manage-direct-io">विभाग 3.9, “Direct I/O”</a>
</div></li><li class="listitem"><div class="para">
<a class="xref" href="#s1-manage-data-journal">विभाग 3.10, “Data Journaling”</a>
</div></li><li class="listitem"><div class="para">
<a class="xref" href="#s1-manage-atimeconf">विभाग 3.11, “Configuring <code class="command">atime</code> Updates”</a>
</div></li><li class="listitem"><div class="para">
<a class="xref" href="#s1-manage-suspendfs">विभाग 3.12, “Suspending Activity on a File System”</a>
</div></li><li class="listitem"><div class="para">
<a class="xref" href="#s1-manage-displaystats">विभाग 3.13, “Displaying Extended GFS Information and Statistics”</a>
</div></li><li class="listitem"><div class="para">
<a class="xref" href="#s1-manage-repairfs">विभाग 3.14, “Repairing a File System”</a>
</div></li><li class="listitem"><div class="para">
<a class="xref" href="#s1-manage-pathnames">विभाग 3.15, “Context-Dependent Path Names”</a>
</div></li><li class="listitem"><div class="para">
<a class="xref" href="#s1-manage-gfswithdraw">विभाग 3.16, “The GFS Withdraw Function”</a>
</div></li></ul></div><div class="section" id="s1-manage-makefs"><div class="titlepage"><div><div><h2 class="title" id="s1-manage-makefs">3.1. Creating a File System</h2></div></div></div><a id="id599982" class="indexterm"></a><a id="id601148" class="indexterm"></a><div class="para">
You can create a GFS file system with the <code class="command">gfs_mkfs</code> command. A file system is created on an activated LVM volume. The following information is required to execute the <code class="command">gfs_mkfs</code> command:
</div><div class="itemizedlist"><ul><li class="listitem"><div class="para">
Lock protocol/module name. The lock protocol for a cluster is <code class="literal">lock_dlm</code>. The lock protocol when GFS is acting as a local file system (one node only) is <code class="literal">lock_nolock</code>.
</div></li><li class="listitem"><div class="para">
Cluster name (when running as part of a cluster configuration).
</div></li><li class="listitem"><div class="para">
Number of journals (one journal required for each node that may be mounting the file systema.) Make sure to account for additional journals needed for future expansion, as you cannot add journals dynamically to a GFS file system.
</div></li></ul></div><div class="para">
When creating a GFS file system, you can use the <code class="command">gfs_mkfs</code> directly, or you can use the <code class="command">mkfs</code> command with the <em class="parameter"><code>-t</code></em> parameter specifying a file system of type <code class="literal">gfs</code>, followed by the gfs file system options.
</div><div class="note"><div class="admonition_header"><h2>Note</h2></div><div class="admonition"><div class="para">
Once you have created a GFS file system with the <code class="command">gfs_mkfs</code> command, you cannot decrease the size of the file system. You can, however, increase the size of an existing file system with the <code class="command">gfs_grow</code> command, as described in <a class="xref" href="#s1-manage-growfs">विभाग 3.7, “Growing a File System”</a>.
</div></div></div><div class="simplesect" id="ss-mkfs-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><div class="para">
When creating a clustered GFS file system, you can use either of the following formats:
</div><pre class="screen">
gfs_mkfs -p <em class="parameter"><code>LockProtoName</code></em> -t <em class="parameter"><code>LockTableName</code></em> -j <em class="parameter"><code>NumberJournals BlockDevice</code></em></pre><pre class="screen">
mkfs -t gfs -p <em class="parameter"><code>LockProtoName</code></em> -t <em class="parameter"><code>LockTableName</code></em> -j <em class="parameter"><code>NumberJournals BlockDevice</code></em></pre><div class="para">
When creating a local file system, you can use either of the following formats:
</div><div class="note"><div class="admonition_header"><h2>टीप</h2></div><div class="admonition"><div class="para">
For the Red Hat Enterprise Linux 5.5 release and later Red Hat does not support the use of GFS as a single-node file system. Red Hat will continue to support single-node GFS file systems for existing customers.
</div></div></div><pre class="screen">
gfs_mkfs -p <em class="parameter"><code>LockProtoName</code></em> -j <em class="parameter"><code>NumberJournals BlockDevice</code></em></pre><pre class="screen">
mkfs -t gfs -p <em class="parameter"><code>LockProtoName</code></em> -j <em class="parameter"><code>NumberJournals BlockDevice</code></em></pre><div class="warning"><div class="admonition_header"><h2>Warning</h2></div><div class="admonition"><div class="para">
Make sure that you are very familiar with using the <em class="parameter"><code>LockProtoName</code></em> and <em class="parameter"><code>LockTableName</code></em> parameters. Improper use of the <em class="parameter"><code>LockProtoName</code></em> and <em class="parameter"><code>LockTableName</code></em> parameters may cause file system or lock space corruption.
</div></div></div><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>LockProtoName</code></em></span></dt><dd><div class="para">
Specifies the name of the locking protocol to use. The lock protocol for a cluster is <code class="literal">lock_dlm</code>. The lock protocol when GFS is acting as a local file system (one node only) is <code class="literal">lock_nolock</code>.
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>LockTableName</code></em></span></dt><dd><div class="para">
This parameter is specified for GFS file system in a cluster configuration. It has two parts separated by a colon (no spaces) as follows: <em class="parameter"><code>ClusterName:FSName</code></em>
</div><div class="itemizedlist"><ul><li class="listitem"><div class="para">
<em class="parameter"><code>ClusterName</code></em>, the name of the Red Hat cluster for which the GFS file system is being created.
</div></li><li class="listitem"><div class="para">
<em class="parameter"><code>FSName</code></em>, the file system name, can be 1 to 16 characters long, and the name must be unique among all file systems in the cluster.
</div></li></ul></div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>NumberJournals</code></em></span></dt><dd><div class="para">
Specifies the number of journals to be created by the <code class="command">gfs_mkfs</code> command. One journal is required for each node that mounts the file system. (More journals than are needed can be specified at creation time to allow for future expansion.)
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>BlockDevice</code></em></span></dt><dd><div class="para">
Specifies a volume.
</div></dd></dl></div></div><div class="simplesect" id="ss-mkfs-ex"><div class="titlepage"><div><div><h1 class="title">Examples</h1></div></div></div><div class="para">
In these examples, <code class="literal">lock_dlm</code> is the locking protocol that the file system uses, since this is a clustered file system. The cluster name is <code class="filename">alpha</code>, and the file system name is <code class="filename">mydata1</code>. The file system contains eight journals and is created on <code class="filename">/dev/vg01/lvol0</code>.
</div><pre class="screen">
[root@ask-07 ~]# <strong class="userinput"><code> gfs_mkfs -p lock_dlm -t alpha:mydata1 -j 8 /dev/vg01/lvol0</code></strong>
This will destroy any data on /dev/vg01/lvol0.
Are you sure you want to proceed? [y/n] y
Device: /dev/vg01/lvol0
Blocksize: 4096
Filesystem Size: 136380192
Journals: 8
Resource Groups: 2082
Locking Protocol: lock_dlm
Lock Table: alpha:mydata1
Syncing...
All Done
</pre><pre class="screen">
[root@ask-07 ~]# <strong class="userinput"><code> mkfs -t gfs -p lock_dlm -t alpha:mydata1 -j 8 /dev/vg01/lvol0</code></strong>
This will destroy any data on /dev/vg01/lvol0.
Are you sure you want to proceed? [y/n] y
Device: /dev/vg01/lvol0
Blocksize: 4096
Filesystem Size: 136380192
Journals: 8
Resource Groups: 2082
Locking Protocol: lock_dlm
Lock Table: alpha:mydata1
Syncing...
All Done
</pre><div class="para">
In these examples, a second <code class="literal">lock_dlm</code> file system is made, which can be used in cluster <code class="filename">alpha</code>. The file system name is <code class="filename">mydata2</code>. The file system contains eight journals and is created on <code class="filename">/dev/vg01/lvol1</code>.
</div><pre class="screen">
gfs_mkfs -p lock_dlm -t alpha:mydata2 -j 8 /dev/vg01/lvol1
</pre><pre class="screen">
mkfs -t gfs -p lock_dlm -t alpha:mydata2 -j 8 /dev/vg01/lvol1
</pre></div><div class="simplesect" id="ss-mkfs-opts"><div class="titlepage"><div><div><h1 class="title">Complete Options</h1></div></div></div><div class="para">
<a class="xref" href="#tb-table-gfs-mkfs">तक्ता 3.1, “Command Options: <code class="command">gfs_mkfs</code>”</a> describes the <code class="command">gfs_mkfs</code> command options.
</div><a id="id642150" class="indexterm"></a><a id="id642165" class="indexterm"></a><div class="table" id="tb-table-gfs-mkfs"><h6>तक्ता 3.1. Command Options: <code class="command">gfs_mkfs</code></h6><div class="table-contents"><table summary="Command Options: gfs_mkfs" border="1"><colgroup><col width="11%" class="Flag" /><col width="33%" class="Parameter" /><col width="56%" class="Description" /></colgroup><thead><tr><th>
Flag
</th><th>
Parameter
</th><th>
Description
</th></tr></thead><tbody><tr><td>
<code class="option">-b</code>
</td><td>
<em class="parameter"><code>BlockSize</code></em>
</td><td>
Sets the file system block size to <em class="parameter"><code>BlockSize</code></em>. Default block size is 4096 bytes.
</td></tr><tr><td>
<code class="option">-D</code>
</td><td>
</td><td>
Enables debugging output.
</td></tr><tr><td>
<code class="option">-h</code>
</td><td>
</td><td>
Help. Displays available options.
</td></tr><tr><td>
<code class="option">-J</code>
</td><td>
<em class="parameter"><code>MegaBytes</code></em>
</td><td>
Specifies the size of the journal in megabytes. Default journal size is 128 megabytes. The minimum size is 32 megabytes.
</td></tr><tr><td>
<code class="option">-j</code>
</td><td>
<em class="parameter"><code>Number</code></em>
</td><td>
<div class="para">
Specifies the number of journals to be created by the <code class="command">gfs_mkfs</code> command. One journal is required for each node that mounts the file system.
</div>
<div class="para">
<span class="guilabel"><strong>Note:</strong></span> More journals than are needed can be specified at creation time to allow for future expansion.
</div>
</td></tr><tr><td>
<code class="option">-p</code>
</td><td>
<em class="parameter"><code>LockProtoName</code></em>
</td><td>
<div class="para">
Specifies the name of the locking protocol to use. Recognized locking protocols include:
</div>
<div class="para">
<code class="literal">lock_dlm</code> — The standard locking module, required for a clustered file system.
</div>
<div class="para">
<code class="literal">lock_nolock</code> — Used when GFS is acting as a local file system (one node only).
</div>
</td></tr><tr><td>
<code class="option">-O</code>
</td><td>
</td><td>
Prevents the <code class="command">gfs_mkfs</code> command from asking for confirmation before writing the file system.
</td></tr><tr><td>
<code class="option">-q</code>
</td><td>
</td><td>
Quiet. Do not display anything.
</td></tr><tr><td>
<code class="option">-r</code>
</td><td>
<em class="parameter"><code>MegaBytes</code></em>
</td><td>
Specifies the size of the resource groups in megabytes. Default resource group size is 256 megabytes.
</td></tr><tr><td>
<code class="option">-s</code>
</td><td>
<em class="parameter"><code>Blocks</code></em>
</td><td>
Specifies the journal-segment size in file system blocks.
</td></tr><tr><td>
<code class="option">-t</code>
</td><td>
<em class="parameter"><code>LockTableName</code></em>
</td><td>
<div class="para">
Used in a clustered file system. This parameter has two parts separated by a colon (no spaces) as follows: <em class="parameter"><code>ClusterName:FSName</code></em>.
</div>
<div class="para">
<em class="parameter"><code>ClusterName</code></em> is the name of the Red Hat cluster for which the GFS file system is being created. The cluster name is set in the <code class="filename">/etc/cluster/cluster.conf</code> file via the <span class="application"><strong>Cluster Configuration Tool</strong></span> and displayed at the <span class="application"><strong>Cluster Status Tool</strong></span> in the Red Hat Cluster Suite cluster management GUI.
</div>
<div class="para">
<em class="parameter"><code>FSName</code></em>, the file system name, can be 1 to 16 characters in length, and the name must be unique among all file systems in the cluster.
</div>
</td></tr><tr><td>
<code class="option">-V</code>
</td><td>
</td><td>
Displays command version information.
</td></tr></tbody></table></div></div><br class="table-break" /></div></div><div class="section" id="s1-manage-mountfs"><div class="titlepage"><div><div><h2 class="title" id="s1-manage-mountfs">3.2. Mounting a File System</h2></div></div></div><a id="id572581" class="indexterm"></a><a id="id572589" class="indexterm"></a><div class="para">
Before you can mount a GFS file system, the file system must exist (refer to <a class="xref" href="#s1-manage-makefs">विभाग 3.1, “Creating a File System”</a>), the volume where the file system exists must be activated, and the supporting clustering and locking systems must be started (refer to <a class="xref" href="#ch-config">धडा 2, <em>Getting Started</em></a> and <span class="emphasis"><em>Configuring and Managing a Red Hat Cluster</em></span>. After those requirements have been met, you can mount the GFS file system as you would any Linux file system.
</div><div class="para">
To manipulate file ACLs, you must mount the file system with the <code class="command"><code class="option">-o</code> acl</code> mount option. If a file system is mounted without the <code class="command"><code class="option">-o</code> acl</code> mount option, users are allowed to view ACLs (with <code class="command">getfacl</code>), but are not allowed to set them (with <code class="command">setfacl</code>).
</div><div class="simplesect" id="ss-gfs-mount-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><div class="para">
<span class="application"><strong>Mounting Without ACL Manipulation</strong></span>
</div><pre class="screen">
mount <em class="parameter"><code>BlockDevice MountPoint</code></em></pre><div class="para">
<span class="application"><strong>Mounting With ACL Manipulation</strong></span>
</div><pre class="screen">
mount -o acl <em class="parameter"><code>BlockDevice MountPoint</code></em></pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><code class="command"><code class="option">-o</code> acl</code></span></dt><dd><div class="para">
GFS-specific option to allow manipulating file ACLs.
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>BlockDevice</code></em></span></dt><dd><div class="para">
Specifies the block device where the GFS file system resides.
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>MountPoint</code></em></span></dt><dd><div class="para">
Specifies the directory where the GFS file system should be mounted.
</div></dd></dl></div></div><div class="simplesect" id="ss-gfs-mount-ex"><div class="titlepage"><div><div><h1 class="title">Example</h1></div></div></div><div class="para">
In this example, the GFS file system on <code class="filename">/dev/vg01/lvol0</code> is mounted on the <code class="filename">/mydata1</code> directory.
</div><pre class="screen">
mount /dev/vg01/lvol0 /mydata1
</pre></div><div class="simplesect" id="ss-gfs-mount-complete"><div class="titlepage"><div><div><h1 class="title">Complete Usage</h1></div></div></div><pre class="screen">
mount <em class="parameter"><code>BlockDevice MountPoint</code></em> -o <em class="parameter"><code>option</code></em></pre><div class="para">
The <code class="option">-o option</code> argument consists of GFS-specific options (refer to <a class="xref" href="#tb-table-gfs-mount">तक्ता 3.2, “GFS-Specific Mount Options”</a>) or acceptable standard Linux <code class="command">mount -o</code> options, or a combination of both. Multiple <em class="parameter"><code>option</code></em> parameters are separated by a comma and no spaces.
</div><div class="note"><div class="admonition_header"><h2>Note</h2></div><div class="admonition"><div class="para">
The <code class="command">mount</code> command is a Linux system command. In addition to using GFS-specific options described in this section, you can use other, standard, <code class="command">mount</code> command options (for example, <code class="option">-r</code>). For information about other Linux <code class="command">mount</code> command options, see the Linux <code class="command">mount</code> man page.
</div></div></div><div class="para">
<a class="xref" href="#tb-table-gfs-mount">तक्ता 3.2, “GFS-Specific Mount Options”</a> describes the available GFS-specific <code class="option">-o option</code> values that can be passed to GFS at mount time.
</div><div class="note"><div class="admonition_header"><h2>टीप</h2></div><div class="admonition"><div class="para">
This table includes descriptions of options that are used with local file systems only For the Red Hat Enterprise Linux 5.5 release and later Red Hat does not support the use of GFS as a single-node file system. Red Hat will continue to support single-node GFS file systems for existing customers.
</div></div></div><a id="id572860" class="indexterm"></a><a id="id572872" class="indexterm"></a><div class="table" id="tb-table-gfs-mount"><h6>तक्ता 3.2. GFS-Specific Mount Options</h6><div class="table-contents"><table summary="GFS-Specific Mount Options" border="1"><colgroup><col width="44%" class="Option" /><col width="56%" class="Description" /></colgroup><thead><tr><th>
Option
</th><th>
Description
</th></tr></thead><tbody><tr><td>
<code class="command">acl</code>
</td><td>
Allows manipulating file ACLs. If a file system is mounted without the <code class="command"> acl</code> mount option, users are allowed to view ACLs (with <code class="command">getfacl</code>), but are not allowed to set them (with <code class="command">setfacl</code>).
</td></tr><tr><td>
<table border="0" summary="Simple list" class="simplelist"><tr><td><code class="command">ignore_local_fs</code> </td></tr><tr><td><span class="guilabel"><strong>Caution:</strong></span> This option should <span class="emphasis"><em>not</em></span> be used when GFS file systems are shared.</td></tr></table>
</td><td>
Forces GFS to treat the file system as a multihost file system. By default, using <code class="literal">lock_nolock</code> automatically turns on the <code class="literal">localcaching</code> and <code class="literal">localflocks</code> flags.
</td></tr><tr><td>
<table border="0" summary="Simple list" class="simplelist"><tr><td><code class="literal">localcaching</code> </td></tr><tr><td><span class="guilabel"><strong>Caution:</strong></span> This option should not be used when GFS file systems are shared.</td></tr></table>
</td><td>
Tells GFS that it is running as a local file system. GFS can then turn on selected optimization capabilities that are not available when running in cluster mode. The <code class="literal">localcaching</code> flag is automatically turned on by <code class="literal">lock_nolock</code>.
</td></tr><tr><td>
<table border="0" summary="Simple list" class="simplelist"><tr><td><code class="literal">localflocks</code> </td></tr><tr><td><span class="guilabel"><strong>Caution:</strong></span> This option should not be used when GFS file systems are shared.</td></tr></table>
</td><td>
<table border="0" summary="Simple list" class="simplelist"><tr><td> Tells GFS to let the VFS (virtual file system) layer do all flock and fcntl. The <code class="literal">localflocks</code> flag is automatically turned on by <code class="literal">lock_nolock</code>. </td></tr><tr><td> Note that the <code class="literal">localflocks</code> mount option affects only advisory <code class="literal">fcntl()</code>/POSIX locks and <code class="literal">flock</code> locks that are issued by applications. The internal locking that ensures coherency of data across the cluster by means of GFS's <code class="literal">glock</code> abstraction is separate from and not affected by the <code class="literal">localflocks</code> setting. </td></tr><tr><td> If you are unsure whether an application uses <code class="literal">fcntl()</code>/POSIX locks and thus requires that you mount your file system with the <code class="literal">localflocks</code>, you can use the <code class="command">strace</code> utility to print out the system calls that are made during a test run of the application. Look for <code class="command">fcntl</code> calls that have <code class="literal">F_GETLK</code>, <code class="literal">F_SETLK</code>, or <code class="literal">F_SETLKW</code> as the <code class="option">cmd</code> argument. </td></tr><tr><td> Note that GFS does not currently support either leases or mandatory locking. </td></tr></table>
</td></tr><tr><td>
<code class="command">lockproto=<em class="parameter"><code>LockModuleName</code></em></code>
</td><td>
Allows the user to specify which locking protocol to use with the file system. If <em class="parameter"><code>LockModuleName</code></em> is not specified, the locking protocol name is read from the file system superblock.
</td></tr><tr><td>
<code class="command">locktable=<em class="parameter"><code>LockTableName</code></em></code>
</td><td>
For a clustered file system, allows the user to specify which locking table to use with the file system.
</td></tr><tr><td>
<code class="command">oopses_ok</code>
</td><td>
<div class="para">
This option allows a GFS node to <span class="emphasis"><em>not</em></span> panic when an oops occurs. (By default, a GFS node panics when an oops occurs, causing the file system used by that node to stall for other GFS nodes.) A GFS node <span class="emphasis"><em>not</em></span> panicking when an oops occurs minimizes the failure on other GFS nodes using the file system that the failed node is using. There may be circumstances where you do not want to use this option — for example, when you need more detailed troubleshooting information. Use this option with care.
</div>
<div class="para">
<span class="guilabel"><strong>Note:</strong></span> This option is turned on automatically if <code class="literal">lock_nolock</code> locking is specified; however, you can override it by using the <code class="literal">ignore_local_fs</code> option.
</div>
</td></tr><tr><td>
<code class="command">upgrade</code>
</td><td>
Upgrade the on-disk format of the file system so that it can be used by newer versions of GFS.
</td></tr><tr><td>
<code class="command">errors=panic|withdraw</code>
</td><td>
When <code class="literal">errors=panic</code> is specified, file system errors will cause a kernel panic. The default behavior, which is the same as specifying <code class="literal">errors=withdraw</code>, is for the system to withdraw from the file system and make it inaccessible until the next reboot; in some cases the system may remain running. For information on the GFS withdraw function, see <a class="xref" href="#s1-manage-gfswithdraw">विभाग 3.16, “The GFS Withdraw Function”</a>.
</td></tr></tbody></table></div></div><br class="table-break" /></div></div><div class="section" id="s1-manage-unmountfs"><div class="titlepage"><div><div><h2 class="title" id="s1-manage-unmountfs">3.3. Unmounting a File System</h2></div></div></div><a id="id580978" class="indexterm"></a><a id="id580986" class="indexterm"></a><div class="para">
The GFS file system can be unmounted the same way as any Linux file system — by using the <code class="command">umount</code> command.
</div><div class="note"><div class="admonition_header"><h2>Note</h2></div><div class="admonition"><div class="para">
The <code class="command">umount</code> command is a Linux system command. Information about this command can be found in the Linux <code class="command">umount</code> command man pages.
</div></div></div><div class="simplesect" id="ss-gfs-unmount-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><pre class="screen">
umount <em class="parameter"><code>MountPoint</code></em></pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>MountPoint</code></em></span></dt><dd><div class="para">
Specifies the directory where the GFS file system should be mounted.
</div></dd></dl></div></div></div><div class="section" id="s1-mount-considerations"><div class="titlepage"><div><div><h2 class="title" id="s1-mount-considerations">3.4. Special Considerations when Mounting GFS File Systems</h2></div></div></div><a id="id581073" class="indexterm"></a><a id="id581081" class="indexterm"></a><a id="id581093" class="indexterm"></a><a id="id581101" class="indexterm"></a><div class="para">
GFS file systems that have been mounted manually rather than automatically through an entry in the <code class="filename">fstab</code> file will not be known to the system when file systems are unmounted at system shutdown. As a result, the GFS script will not unmount the GFS file system. After the GFS shutdown script is run, the standard shutdown process kills off all remaining user processes, including the cluster infrastructure, and tries to unmount the file system. This unmount will fail without the cluster infrastructure and the system will hang.
</div><div class="para">
To prevent the system from hanging when the GFS file systems are unmounted, you should do one of the following:
</div><div class="itemizedlist"><ul><li class="listitem"><div class="para">
Always use an entry in the <code class="filename">fstab</code> file to mount the GFS file system.
</div></li><li class="listitem"><div class="para">
If a GFS file system has been mounted manually with the <code class="command">mount</code> command, be sure to unmount the file system manually with the <code class="command">umount</code> command before rebooting or shutting down the system.
</div></li></ul></div><a id="id581162" class="indexterm"></a><a id="id581170" class="indexterm"></a><div class="para">
If your file system hangs while it is being unmounted during system shutdown under these circumstances, perform a hardware reboot. It is unlikely that any data will be lost since the file system is synced earlier in the shutdown process.
</div></div><div class="section" id="s1-manage-tunables"><div class="titlepage"><div><div><h2 class="title" id="s1-manage-tunables">3.5. Displaying GFS Tunable Parameters</h2></div></div></div><a id="id581193" class="indexterm"></a><a id="id581201" class="indexterm"></a><div class="para">
There are a variety of parameters associated with a GFS file system that you can modify with the <code class="command">gfs_tool settune</code> command. Some of these parameters are used to administer GFS quotas: <code class="literal">quota_quantum</code>, <code class="literal">quota_enforce</code>, <code class="literal">quota_account</code>, and <code class="literal">atime_quantum</code>. These parameters are described in <a class="xref" href="#s1-manage-quota">विभाग 3.6, “GFS Quota Management”</a>, along with examples of how to modify them.
</div><div class="para">
Parameters that you set with the <code class="command">gfs_tool settune</code> command must be set on each node each time the file system is mounted. These parameters are not persistent across mounts.
</div><div class="note"><div class="admonition_header"><h2>टीप</h2></div><div class="admonition"><div class="para">
The majority of the tunable parameters are internal parameters. They are intended for development purposes only and should not be changed.
</div></div></div><div class="para">
The <code class="command">gfs_tool gettune</code> command displays a listing of the current values of the GFS tunable parameters.
</div><div class="simplesect" id="ss-manage-tunabledisplay-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><div class="para">
<span class="application"><strong>Display Tunable Parameters</strong></span>
</div><pre class="screen">
gfs_tool gettune <em class="parameter"><code>MountPoint</code></em></pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>MountPoint</code></em></span></dt><dd><div class="para">
Specifies the directory where the GFS file system is mounted.
</div></dd></dl></div></div><div class="simplesect" id="ss-manage-tuneabledisplay-ex"><div class="titlepage"><div><div><h1 class="title">Examples</h1></div></div></div><div class="para">
In this example, all GFS tunable parameters for the file system on the mount point <code class="filename">/mnt/gfs</code> are displayed.
</div><pre class="screen">
[root@tng3-1]# <strong class="userinput"><code>gfs_tool gettune /mnt/gfs</code></strong>
ilimit1 = 100
ilimit1_tries = 3
ilimit1_min = 1
ilimit2 = 500
ilimit2_tries = 10
ilimit2_min = 3
demote_secs = 300
incore_log_blocks = 1024
jindex_refresh_secs = 60
depend_secs = 60
scand_secs = 5
recoverd_secs = 60
logd_secs = 1
quotad_secs = 5
inoded_secs = 15
glock_purge = 0
quota_simul_sync = 64
quota_warn_period = 10
atime_quantum = 3600
quota_quantum = 60
quota_scale = 1.0000 (1, 1)
quota_enforce = 1
quota_account = 1
new_files_jdata = 0
new_files_directio = 0
max_atomic_write = 4194304
max_readahead = 262144
lockdump_size = 131072
stall_secs = 600
complain_secs = 10
reclaim_limit = 5000
entries_per_readdir = 32
prefetch_secs = 10
statfs_slots = 64
max_mhc = 10000
greedy_default = 100
greedy_quantum = 25
greedy_max = 250
rgrp_try_threshold = 100
statfs_fast = 0
</pre></div></div><div class="section" id="s1-manage-quota"><div class="titlepage"><div><div><h2 class="title" id="s1-manage-quota">3.6. GFS Quota Management</h2></div></div></div><a id="id581349" class="indexterm"></a><a id="id581361" class="indexterm"></a><a id="id581369" class="indexterm"></a><div class="para">
File-system quotas are used to limit the amount of file system space a user or group can use. A user or group does not have a quota limit until one is set. GFS keeps track of the space used by each user and group even when there are no limits in place. GFS updates quota information in a transactional way so system crashes do not require quota usages to be reconstructed.
</div><div class="para">
To prevent a performance slowdown, a GFS node synchronizes updates to the quota file only periodically. The "fuzzy" quota accounting can allow users or groups to slightly exceed the set limit. To minimize this, GFS dynamically reduces the synchronization period as a "hard" quota limit is approached.
</div><div class="para">
GFS uses its <code class="command">gfs_quota</code> command to manage quotas. Other Linux quota facilities cannot be used with GFS.
</div><div class="section" id="s2-manage-setquota"><div class="titlepage"><div><div><h3 class="title" id="s2-manage-setquota">3.6.1. Setting Quotas</h3></div></div></div><a id="id581411" class="indexterm"></a><a id="id581427" class="indexterm"></a><a id="id581439" class="indexterm"></a><div class="para">
Two quota settings are available for each user ID (UID) or group ID (GID): a <em class="firstterm">hard limit</em> and a <em class="firstterm">warn limit</em>.
</div><div class="para">
A hard limit is the amount of space that can be used. The file system will not let the user or group use more than that amount of disk space. A hard limit value of <span class="emphasis"><em>zero</em></span> means that no limit is enforced.
</div><div class="para">
A warn limit is usually a value less than the hard limit. The file system will notify the user or group when the warn limit is reached to warn them of the amount of space they are using. A warn limit value of <span class="emphasis"><em>zero</em></span> means that no limit is enforced.
</div><div class="para">
Limits are set using the <code class="command">gfs_quota</code> command. The command only needs to be run on a single node where GFS is mounted.
</div><div class="simplesect" id="ss-manage-setquota-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><div class="para">
<span class="application"><strong>Setting Quotas, Hard Limit</strong></span>
</div><pre class="screen">
gfs_quota limit -u <em class="parameter"><code>User</code></em> -l <em class="parameter"><code>Size</code></em> -f <em class="parameter"><code>MountPoint</code></em></pre><pre class="screen">
gfs_quota limit -g <em class="parameter"><code>Group</code></em> -l <em class="parameter"><code>Size</code></em> -f <em class="parameter"><code>MountPoint</code></em></pre><div class="para">
<span class="application"><strong>Setting Quotas, Warn Limit</strong></span>
</div><pre class="screen">
gfs_quota warn -u <em class="parameter"><code>User</code></em> -l <em class="parameter"><code>Size</code></em> -f <em class="parameter"><code>MountPoint</code></em></pre><pre class="screen">
gfs_quota warn -g <em class="parameter"><code>Group</code></em> -l <em class="parameter"><code>Size</code></em> -f <em class="parameter"><code>MountPoint</code></em></pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>User</code></em></span></dt><dd><div class="para">
A user ID to limit or warn. It can be either a user name from the password file or the UID number.
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>Group</code></em></span></dt><dd><div class="para">
A group ID to limit or warn. It can be either a group name from the group file or the GID number.
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>Size</code></em></span></dt><dd><div class="para">
Specifies the new value to limit or warn. By default, the value is in units of megabytes. The additional <code class="option">-k</code>, <code class="option">-s</code> and <code class="option">-b</code> flags change the units to kilobytes, sectors, and file system blocks, respectively.
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>MountPoint</code></em></span></dt><dd><div class="para">
Specifies the GFS file system to which the actions apply.
</div></dd></dl></div></div><div class="simplesect" id="ss-manage-setquota-ex"><div class="titlepage"><div><div><h1 class="title">Examples</h1></div></div></div><div class="para">
This example sets the hard limit for user <em class="replaceable"><code>Bert</code></em> to 1024 megabytes (1 gigabyte) on file system <code class="filename">/gfs</code>.
</div><pre class="screen">
gfs_quota limit -u Bert -l 1024 -f /gfs
</pre><div class="para">
This example sets the warn limit for group ID 21 to 50 kilobytes on file system <code class="filename">/gfs</code>.
</div><pre class="screen">
gfs_quota warn -g 21 -l 50 -k -f /gfs
</pre></div></div><div class="section" id="s2-manage-displayquota"><div class="titlepage"><div><div><h3 class="title" id="s2-manage-displayquota">3.6.2. Displaying Quota Limits and Usage</h3></div></div></div><a id="id581711" class="indexterm"></a><a id="id581727" class="indexterm"></a><a id="id581739" class="indexterm"></a><div class="para">
Quota limits and current usage can be displayed for a specific user or group using the <code class="command">gfs_quota get</code> command. The entire contents of the quota file can also be displayed using the <code class="command">gfs_quota list</code> command, in which case all IDs with a non-zero hard limit, warn limit, or value are listed.
</div><div class="simplesect" id="ss-manage-displayquota-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><div class="para">
<span class="application"><strong>Displaying Quota Limits for a User</strong></span>
</div><pre class="screen">
gfs_quota get -u <em class="parameter"><code>User</code></em> -f <em class="parameter"><code>MountPoint</code></em></pre><div class="para">
<span class="application"><strong>Displaying Quota Limits for a Group</strong></span>
</div><pre class="screen">
gfs_quota get -g <em class="parameter"><code>Group</code></em> -f <em class="parameter"><code>MountPoint</code></em></pre><div class="para">
<span class="application"><strong>Displaying Entire Quota File</strong></span>
</div><pre class="screen">
gfs_quota list -f <em class="parameter"><code>MountPoint</code></em></pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>User</code></em></span></dt><dd><div class="para">
A user ID to display information about a specific user. It can be either a user name from the password file or the UID number.
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>Group</code></em></span></dt><dd><div class="para">
A group ID to display information about a specific group. It can be either a group name from the group file or the GID number.
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>MountPoint</code></em></span></dt><dd><div class="para">
Specifies the GFS file system to which the actions apply.
</div></dd></dl></div></div><div class="simplesect" id="ss-manage-displayquota-output"><div class="titlepage"><div><div><h1 class="title">Command Output</h1></div></div></div><div class="para">
GFS quota information from the <code class="command">gfs_quota</code> command is displayed as follows:
</div><pre class="screen">
user <em class="parameter"><code>User</code></em>: limit:<em class="parameter"><code>LimitSize</code></em> warn:<em class="parameter"><code>WarnSize</code></em> value:<em class="parameter"><code>Value</code></em>
group <em class="parameter"><code>Group</code></em>: limit:<em class="parameter"><code>LimitSize</code></em> warn:<em class="parameter"><code>WarnSize</code></em> value:<em class="parameter"><code>Value</code></em>
</pre><div class="para">
The <em class="parameter"><code>LimitSize</code></em>, <em class="parameter"><code>WarnSize</code></em>, and <em class="parameter"><code>Value</code></em> numbers (values) are in units of megabytes by default. Adding the <code class="option">-k</code>, <code class="option">-s</code>, or <code class="option">-b</code> flags to the command line change the units to kilobytes, sectors, or file system blocks, respectively.
</div><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>User</code></em></span></dt><dd><div class="para">
A user name or ID to which the data is associated.
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>Group</code></em></span></dt><dd><div class="para">
A group name or ID to which the data is associated.
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>LimitSize</code></em></span></dt><dd><div class="para">
The hard limit set for the user or group. This value is zero if no limit has been set.
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>Value</code></em></span></dt><dd><div class="para">
The actual amount of disk space used by the user or group.
</div></dd></dl></div></div><div class="simplesect" id="ss-manage-displayquota-comm"><div class="titlepage"><div><div><h1 class="title">Comments</h1></div></div></div><div class="para">
When displaying quota information, the <code class="command">gfs_quota</code> command does not resolve UIDs and GIDs into names if the <code class="option">-n</code> option is added to the command line.
</div><div class="para">
Space allocated to GFS's hidden files can be left out of displayed values for the root UID and GID by adding the <code class="option">-d</code> option to the command line. This is useful when trying to match the numbers from <code class="command">gfs_quota</code> with the results of a <code class="command">du</code> command.
</div></div><div class="simplesect" id="ss-manage-displayquota-ex"><div class="titlepage"><div><div><h1 class="title">Examples</h1></div></div></div><div class="para">
This example displays quota information for all users and groups that have a limit set or are using any disk space on file system <code class="filename">/gfs</code>.
</div><pre class="screen">
[root@ask-07 ~]# <strong class="userinput"><code>gfs_quota list -f /gfs</code></strong>
user root: limit: 0.0 warn: 0.0 value: 0.2
user moe: limit: 1024.0 warn: 0.0 value: 0.0
group root: limit: 0.0 warn: 0.0 value: 0.2
group stooges: limit: 0.0 warn: 0.0 value: 0.0
</pre><div class="para">
This example displays quota information in sectors for group <code class="filename">users</code> on file system <code class="filename">/gfs</code>.
</div><pre class="screen">
[root@ask-07 ~]# <strong class="userinput"><code>gfs_quota get -g users -f /gfs -s</code></strong>
group users: limit: 0 warn: 96 value: 0
</pre></div></div><div class="section" id="s2-manage-synchquota"><div class="titlepage"><div><div><h3 class="title" id="s2-manage-synchquota">3.6.3. Synchronizing Quotas</h3></div></div></div><a id="id594642" class="indexterm"></a><a id="id594658" class="indexterm"></a><a id="id594670" class="indexterm"></a><div class="para">
GFS stores all quota information in its own internal file on disk. A GFS node does not update this quota file for every file system write; rather, it updates the quota file once every 60 seconds. This is necessary to avoid contention among nodes writing to the quota file, which would cause a slowdown in performance.
</div><div class="para">
As a user or group approaches their quota limit, GFS dynamically reduces the time between its quota-file updates to prevent the limit from being exceeded. The normal time period between quota synchronizations is a tunable parameter, <code class="literal">quota_quantum</code>, and can be changed using the <code class="command">gfs_tool</code> command. By default, the time period is 60 seconds. Also, the <code class="literal">quota_quantum</code> parameter must be set on each node and each time the file system is mounted. (Changes to the <code class="command">quota_quantum</code> parameter are not persistent across unmounts.)
</div><div class="para">
To see the current values of the GFS tunable parameters, including <code class="literal">quota_quantum</code>, you can use the <code class="command">gfs_tool gettune</code>, as described in <a class="xref" href="#s1-manage-tunables">विभाग 3.5, “Displaying GFS Tunable Parameters”</a>.
</div><div class="para">
You can use the <code class="command">gfs_quota sync</code> command to synchronize the quota information from a node to the on-disk quota file between the automatic updates performed by GFS.
</div><div class="simplesect" id="ss-manage-synchquota-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><div class="para">
<span class="application"><strong>Synchronizing Quota Information</strong></span>
</div><pre class="screen">
gfs_quota sync -f <em class="parameter"><code>MountPoint</code></em></pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>MountPoint</code></em></span></dt><dd><div class="para">
Specifies the GFS file system to which the actions apply.
</div></dd></dl></div><div class="para">
<span class="application"><strong>Tuning the Time Between Synchronizations</strong></span>
</div><pre class="screen">
gfs_tool settune <em class="parameter"><code>MountPoint</code></em> quota_quantum <em class="parameter"><code>Seconds</code></em></pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>MountPoint</code></em></span></dt><dd><div class="para">
Specifies the GFS file system to which the actions apply.
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>Seconds</code></em></span></dt><dd><div class="para">
Specifies the new time period between regular quota-file synchronizations by GFS. Smaller values may increase contention and slow down performance.
</div></dd></dl></div></div><div class="simplesect" id="ss-manage-synchquota-ex"><div class="titlepage"><div><div><h1 class="title">Examples</h1></div></div></div><div class="para">
This example synchronizes the quota information from the node it is run on to file system <code class="filename">/gfs</code>.
</div><pre class="screen">
gfs_quota sync -f /gfs
</pre><div class="para">
This example changes the default time period between regular quota-file updates to one hour (3600 seconds) for file system <code class="filename">/gfs</code> on a single node.
</div><pre class="screen">
gfs_tool settune /gfs quota_quantum 3600
</pre></div></div><div class="section" id="s2-manage-enablequota"><div class="titlepage"><div><div><h3 class="title" id="s2-manage-enablequota">3.6.4. Disabling/Enabling Quota Enforcement</h3></div></div></div><a id="id594892" class="indexterm"></a><a id="id594908" class="indexterm"></a><a id="id594919" class="indexterm"></a><div class="para">
Enforcement of quotas can be disabled for a file system without clearing the limits set for all users and groups. Enforcement can also be enabled. Disabling and enabling of quota enforcement is done by changing a tunable parameter, <code class="command">quota_enforce</code>, with the <code class="command">gfs_tool</code> command. The <code class="command">quota_enforce</code> parameter must be disabled or enabled on each node where quota enforcement should be disabled/enabled. Each time the file system is mounted, enforcement is enabled by default. (Disabling is not persistent across unmounts.)
</div><div class="para">
To see the current values of the GFS tunable parameters, including <code class="literal">quota_enforce</code>, you can use the <code class="command">gfs_tool gettune</code>, as described in <a class="xref" href="#s1-manage-tunables">विभाग 3.5, “Displaying GFS Tunable Parameters”</a>.
</div><div class="simplesect" id="ss-manage-enablequota-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><pre class="screen">
gfs_tool settune <em class="parameter"><code>MountPoint</code></em> quota_enforce {0|1}
</pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>MountPoint</code></em></span></dt><dd><div class="para">
Specifies the GFS file system to which the actions apply.
</div></dd><dt class="varlistentry"><span class="term"><code class="command">quota_enforce {0|1}</code></span></dt><dd><div class="para">
0 = disabled
</div><div class="para">
1 = enabled
</div></dd></dl></div></div><div class="simplesect" id="ss-manage-enablequota-comm"><div class="titlepage"><div><div><h1 class="title">Comments</h1></div></div></div><div class="para">
A value of 0 disables enforcement. Enforcement can be enabled by running the command with a value of 1 (instead of 0) as the final command line parameter. Even when GFS is not enforcing quotas, it still keeps track of the file system usage for all users and groups so that quota-usage information does not require rebuilding after re-enabling quotas.
</div></div><div class="simplesect" id="ss-manage-enablequota-ex"><div class="titlepage"><div><div><h1 class="title">Examples</h1></div></div></div><div class="para">
This example <span class="emphasis"><em>disables</em></span> quota enforcement on file system <code class="filename">/gfs</code>.
</div><pre class="screen">
gfs_tool settune /gfs quota_enforce 0
</pre><div class="para">
This example <span class="emphasis"><em>enables</em></span> quota enforcement on file system <code class="filename">/gfs</code>.
</div><pre class="screen">
gfs_tool settune /gfs quota_enforce 1
</pre></div></div><div class="section" id="s2-manage-quotaaccount"><div class="titlepage"><div><div><h3 class="title" id="s2-manage-quotaaccount">3.6.5. Disabling/Enabling Quota Accounting</h3></div></div></div><a id="id595101" class="indexterm"></a><a id="id595117" class="indexterm"></a><a id="id595128" class="indexterm"></a><div class="para">
By default, quota accounting is enabled; therefore, GFS keeps track of disk usage for every user and group even when no quota limits have been set. Quota accounting incurs unnecessary overhead if quotas are not used. You can disable quota accounting completely by setting the <code class="command">quota_account</code> tunable parameter to 0. This must be done on each node and after each mount. (The 0 setting is not persistent across unmounts.) Quota accounting can be enabled by setting the <code class="command">quota_account</code> tunable parameter to 1.
</div><div class="para">
To see the current values of the GFS tunable parameters, including <code class="literal">quota_account</code>, you can use the <code class="command">gfs_tool gettune</code>, as described in <a class="xref" href="#s1-manage-tunables">विभाग 3.5, “Displaying GFS Tunable Parameters”</a>.
</div><div class="simplesect" id="ss-manage-quotaacct-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><pre class="screen">
gfs_tool settune <em class="parameter"><code>MountPoint</code></em> quota_account {0|1}
</pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>MountPoint</code></em></span></dt><dd><div class="para">
Specifies the GFS file system to which the actions apply.
</div></dd><dt class="varlistentry"><span class="term"><code class="command">quota_account {0|1}</code></span></dt><dd><div class="para">
0 = disabled
</div><div class="para">
1 = enabled
</div></dd></dl></div></div><div class="simplesect" id="ss-manage-quotaacct-comm"><div class="titlepage"><div><div><h1 class="title">Comments</h1></div></div></div><div class="para">
To enable quota accounting on a file system, the <code class="command">quota_account</code> parameter must be set back to 1. Afterward, the GFS quota file must be initialized to account for all current disk usage for users and groups on the file system. The quota file is initialized by running: <code class="command">gfs_quota init -f <em class="parameter"><code>MountPoint</code></em></code>.
</div><div class="note"><div class="admonition_header"><h2>Note</h2></div><div class="admonition"><div class="para">
Initializing the quota file requires scanning the entire file system and may take a long time.
</div></div></div><div class="para">
To see the current values of the GFS tunable parameters, including <code class="literal">quota_account</code>, you can use the <code class="command">gfs_tool gettune</code>, as described in <a class="xref" href="#s1-manage-tunables">विभाग 3.5, “Displaying GFS Tunable Parameters”</a>.
</div></div><div class="simplesect" id="ss-manage-quotaacct-ex"><div class="titlepage"><div><div><h1 class="title">Examples</h1></div></div></div><div class="para">
This example <span class="emphasis"><em>disables</em></span> quota accounting on file system <code class="filename">/gfs</code> on a single node.
</div><pre class="screen">
gfs_tool settune /gfs quota_account 0
</pre><div class="para">
This example enables quota accounting on file system <code class="filename">/gfs</code> on a single node and initializes the quota file.
</div><pre class="screen">
# <strong class="userinput"><code>gfs_tool settune /gfs quota_account 1</code></strong>
# <strong class="userinput"><code>gfs_quota init -f /gfs</code></strong></pre></div></div></div><div class="section" id="s1-manage-growfs"><div class="titlepage"><div><div><h2 class="title" id="s1-manage-growfs">3.7. Growing a File System</h2></div></div></div><a id="id595351" class="indexterm"></a><a id="id595359" class="indexterm"></a><div class="para">
The <code class="command">gfs_grow</code> command is used to expand a GFS file system after the device where the file system resides has been expanded. Running a <code class="command">gfs_grow</code> command on an existing GFS file system fills all spare space between the current end of the file system and the end of the device with a newly initialized GFS file system extension. When the fill operation is completed, the resource index for the file system is updated. All nodes in the cluster can then use the extra storage space that has been added.
</div><div class="para">
The <code class="command">gfs_grow</code> command must be run on a mounted file system, but only needs to be run on one node in a cluster. All the other nodes sense that the expansion has occurred and automatically start using the new space.
</div><div class="para">
To verify that the changes were successful, use the <code class="command">gfs_grow</code> command with the <code class="option">-T</code> (test) and <code class="option">-v</code> (verbose) flags. Running the command with those flags displays the current state of the mounted GFS file system.
</div><div class="note"><div class="admonition_header"><h2>Note</h2></div><div class="admonition"><div class="para">
Once you have created a GFS file system with the <code class="command">gfs_mkfs</code> command, you cannot decrease the size of the file system.
</div></div></div><div class="simplesect" id="ss-manage-growfs-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><pre class="screen">
gfs_grow <em class="parameter"><code>MountPoint</code></em></pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>MountPoint</code></em></span></dt><dd><div class="para">
Specifies the GFS file system to which the actions apply.
</div></dd></dl></div></div><div class="simplesect" id="ss-manage-growfs-comm"><div class="titlepage"><div><div><h1 class="title">Comments</h1></div></div></div><div class="para">
Before running the <code class="command">gfs_grow</code> command:
</div><div class="itemizedlist"><ul><li class="listitem"><div class="para">
Back up important data on the file system.
</div></li><li class="listitem"><div class="para">
Display the volume that is used by the file system to be expanded by running a <code class="command">df <em class="parameter"><code>MountPoint</code></em></code> command.
</div></li><li class="listitem"><div class="para">
Expand the underlying cluster volume with LVM. For information on administering LVM volumes, see <em class="citetitle">Logical Volume Manager Administration</em>.
</div></li></ul></div><div class="para">
The <code class="command">gfs_grow</code> command provides a <code class="option">-T</code> (test) option that allows you to see the results of executing the command without actually expanding the file system. Using this command with the <code class="option">-v</code> provides additional information.
</div><div class="para">
After running the <code class="command">gfs_grow</code> command, you can run a <code class="command">df <em class="parameter"><code>MountPoint</code></em></code> command on the file system to check that the new space is now available in the file system.
</div></div><div class="simplesect" id="ss-manage-growfs-ex"><div class="titlepage"><div><div><h1 class="title">Examples</h1></div></div></div><div class="para">
In this example, the underlying logical volume for the file system file system on the <code class="filename">/mnt/gfs</code> directory is extended, and then the file system is expanded.
</div><pre class="screen">
[root@tng3-1 ~]# <strong class="userinput"><code>lvextend -L35G /dev/gfsvg/gfslv</code></strong>
Extending logical volume gfslv to 35.00 GB
Logical volume gfslv successfully resized
[root@tng3-1 ~]# <strong class="userinput"><code>gfs_grow /mnt/gfs</code></strong>
FS: Mount Point: /mnt/gfs
FS: Device: /dev/mapper/gfsvg-gfslv
FS: Options: rw,hostdata=jid=0:id=196609:first=1
FS: Size: 5341168
DEV: Size: 9175040
Preparing to write new FS information...
Done.
</pre></div><div class="simplesect" id="ss-manage-growfs-complete"><div class="titlepage"><div><div><h1 class="title">Complete Usage</h1></div></div></div><pre class="screen">
gfs_grow [<em class="parameter"><code>Options</code></em>] {<em class="parameter"><code>MountPoint</code></em> | <em class="parameter"><code>Device</code></em>} [<em class="parameter"><code>MountPoint</code></em> | <em class="parameter"><code>Device</code></em>]
</pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>MountPoint</code></em></span></dt><dd><div class="para">
Specifies the directory where the GFS file system is mounted.
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>Device</code></em></span></dt><dd><div class="para">
Specifies the device node of the file system.
</div></dd></dl></div><div class="para">
<a class="xref" href="#tb-table-gfs-expandfs">तक्ता 3.3, “GFS-specific Options Available While Expanding A File System”</a> describes the GFS-specific options that can be used while expanding a GFS file system.
</div><a id="id595674" class="indexterm"></a><a id="id595686" class="indexterm"></a><div class="table" id="tb-table-gfs-expandfs"><h6>तक्ता 3.3. GFS-specific Options Available While Expanding A File System</h6><div class="table-contents"><table summary="GFS-specific Options Available While Expanding A File System" border="1"><colgroup><col width="29%" class="Option" /><col width="71%" class="Description" /></colgroup><thead><tr><th>
Option
</th><th>
Description
</th></tr></thead><tbody><tr><td>
<code class="option">-h</code>
</td><td>
Help. Displays a short usage message.
</td></tr><tr><td>
<code class="option">-q</code>
</td><td>
Quiet. Turns down the verbosity level.
</td></tr><tr><td>
<code class="option">-T</code>
</td><td>
Test. Do all calculations, but do not write any data to the disk and do not expand the file system.
</td></tr><tr><td>
<code class="option">-V</code>
</td><td>
Displays command version information.
</td></tr><tr><td>
<code class="option">-v</code>
</td><td>
Turns up the verbosity of messages.
</td></tr></tbody></table></div></div><br class="table-break" /></div></div><div class="section" id="s1-manage-addjournalfs"><div class="titlepage"><div><div><h2 class="title" id="s1-manage-addjournalfs">3.8. Adding Journals to a File System</h2></div></div></div><a id="id595844" class="indexterm"></a><a id="id595851" class="indexterm"></a><div class="para">
The <code class="command">gfs_jadd</code> command is used to add journals to a GFS file system after the device where the file system resides has been expanded. Running a <code class="command">gfs_jadd</code> command on a GFS file system uses space between the current end of the file system and the end of the device where the file system resides. When the fill operation is completed, the journal index is updated.
</div><div class="para">
The <code class="command">gfs_jadd</code> command must be run on mounted file system, but it only needs to be run on one node in the cluster. All the other nodes sense that the expansion has occurred.
</div><div class="para">
To verify that the changes were successful, use the <code class="command">gfs_jadd</code> command with the <code class="option">-T</code> (test) and <code class="option">-v</code> (verbose) flags. Running the command with those flags displays the current state of the mounted GFS file system.
</div><div class="simplesect" id="ss-manage-addjournal-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><pre class="screen">
gfs_jadd -j <em class="parameter"><code>Number MountPoint</code></em></pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>Number</code></em></span></dt><dd><div class="para">
Specifies the number of new journals to be added.
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>MountPoint</code></em></span></dt><dd><div class="para">
Specifies the directory where the GFS file system is mounted.
</div></dd></dl></div></div><div class="simplesect" id="ss-manage-addjournal-comm"><div class="titlepage"><div><div><h1 class="title">Comments</h1></div></div></div><div class="para">
Before running the <code class="command">gfs_jadd</code> command:
</div><div class="itemizedlist"><ul><li class="listitem"><div class="para">
Back up important data on the file system.
</div></li><li class="listitem"><div class="para">
Run a <code class="command">df <em class="parameter"><code>MountPoint</code></em></code> command to display the volume used by the file system where journals will be added.
</div></li><li class="listitem"><div class="para">
Expand the underlying cluster volume with LVM. For information on administering LVM volumes, see the <span class="emphasis"><em>LVM Administrator's Guide</em></span>
</div></li></ul></div><div class="para">
You can find out how many journals are currently used by the file system with the <code class="command">gfs_tool df <em class="parameter"><code>MountPoint</code></em></code> command. In the following example, the file system mounted at <code class="filename">/mnt/gfs</code> uses 8 journals.
</div><pre class="screen">
[root@tng3-1 gfs]# <strong class="userinput"><code>gfs_tool df /mnt/gfs</code></strong>
/mnt/gfs:
SB lock proto = "lock_dlm"
SB lock table = "tng3-cluster:mydata1"
SB ondisk format = 1309
SB multihost format = 1401
Block size = 4096
Journals = 8
Resource Groups = 76
Mounted lock proto = "lock_dlm"
Mounted lock table = "tng3-cluster:mydata1"
Mounted host data = "jid=0:id=196609:first=1"
Journal number = 0
Lock module flags = 0
Local flocks = FALSE
Local caching = FALSE
Oopses OK = FALSE
Type Total Used Free use%
------------------------------------------------------------------------
inodes 33 33 0 100%
metadata 38 2 36 5%
data 4980077 178 4979899 0%
</pre><div class="para">
After running the <code class="command">gfs_jadd</code> command, you can run the <code class="command">gfs_tool df <em class="parameter"><code>MountPoint</code></em></code> command again to check that the new journals have been added to the file system.
</div></div><div class="simplesect" id="ss-manage-addjournal-ex"><div class="titlepage"><div><div><h1 class="title">Examples</h1></div></div></div><div class="para">
In this example, one journal is added to the file system that is mounted at the <code class="filename">/mnt/gfs</code> directory. The underlying logical volume for this file system is extended before the journal can be added.
</div><pre class="screen">
[root@tng3-1 ~]# <strong class="userinput"><code>lvextend -L35G /dev/gfsvg/gfslv</code></strong>
Extending logical volume gfslv to 35.00 GB
Logical volume gfslv successfully resized
[root@tng3-1 ~]# <strong class="userinput"><code>gfs_jadd -j1 /mnt/gfs</code></strong>
FS: Mount Point: /mnt/gfs
FS: Device: /dev/mapper/gfsvg-gfslv
FS: Options: rw,hostdata=jid=0:id=196609:first=1
FS: Size: 5242877
DEV: Size: 9175040
Preparing to write new FS information...
Done.
</pre><div class="para">
In this example, two journals are added to the file system on the <code class="filename">/mnt/gfs</code> directory.
</div><pre class="screen">
[root@tng3-1 ~]# <strong class="userinput"><code>gfs_jadd -j2 /mnt/gfs</code></strong>
FS: Mount Point: /mnt/gfs
FS: Device: /dev/mapper/gfsvg-gfslv
FS: Options: rw,hostdata=jid=0:id=196609:first=1
FS: Size: 5275632
DEV: Size: 9175040
Preparing to write new FS information...
Done.
</pre></div><div class="simplesect" id="ss-manage-addjournal-complete"><div class="titlepage"><div><div><h1 class="title">Complete Usage</h1></div></div></div><pre class="screen">
gfs_jadd [<em class="parameter"><code>Options</code></em>] {<em class="parameter"><code>MountPoint</code></em> | <em class="parameter"><code>Device</code></em>} [<em class="parameter"><code>MountPoint</code></em> | <em class="parameter"><code>Device</code></em>]
</pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>MountPoint</code></em></span></dt><dd><div class="para">
Specifies the directory where the GFS file system is mounted.
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>Device</code></em></span></dt><dd><div class="para">
Specifies the device node of the file system.
</div></dd></dl></div><div class="para">
<a class="xref" href="#tb-table-gfs-addjournal">तक्ता 3.4, “GFS-specific Options Available When Adding Journals”</a> describes the GFS-specific options that can be used when adding journals to a GFS file system.
</div><a id="id596194" class="indexterm"></a><a id="id596206" class="indexterm"></a><div class="table" id="tb-table-gfs-addjournal"><h6>तक्ता 3.4. GFS-specific Options Available When Adding Journals</h6><div class="table-contents"><table summary="GFS-specific Options Available When Adding Journals" border="1"><colgroup><col width="14%" class="Flag" /><col width="29%" class="Parameter" /><col width="57%" class="Description" /></colgroup><thead><tr><th>
Flag
</th><th>
Parameter
</th><th>
Description
</th></tr></thead><tbody><tr><td>
<code class="option">-h</code>
</td><td>
</td><td>
Help. Displays short usage message.
</td></tr><tr><td>
<code class="option">-J</code>
</td><td>
<em class="parameter"><code>MegaBytes</code></em>
</td><td>
Specifies the size of the new journals in megabytes. Default journal size is 128 megabytes. The minimum size is 32 megabytes. To add journals of different sizes to the file system, the <code class="command">gfs_jadd</code> command must be run for each size journal. The size specified is rounded down so that it is a multiple of the journal-segment size that was specified when the file system was created.
</td></tr><tr><td>
<code class="option">-j</code>
</td><td>
<em class="parameter"><code>Number</code></em>
</td><td>
Specifies the number of new journals to be added by the <code class="command">gfs_jadd</code> command. The default value is 1.
</td></tr><tr><td>
<code class="option">-T</code>
</td><td>
</td><td>
Test. Do all calculations, but do not write any data to the disk and do not add journals to the file system. Enabling this flag helps discover what the <code class="command">gfs_jadd</code> command would have done if it were run without this flag. Using the <code class="option">-v</code> flag with the <code class="option">-T</code> flag turns up the verbosity level to display more information.
</td></tr><tr><td>
<code class="option">-q</code>
</td><td>
</td><td>
Quiet. Turns down the verbosity level.
</td></tr><tr><td>
<code class="option">-V</code>
</td><td>
</td><td>
Displays command version information.
</td></tr><tr><td>
<code class="option">-v</code>
</td><td>
</td><td>
Turns up the verbosity of messages.
</td></tr></tbody></table></div></div><br class="table-break" /></div></div><div class="section" id="s1-manage-direct-io"><div class="titlepage"><div><div><h2 class="title" id="s1-manage-direct-io">3.9. Direct I/O</h2></div></div></div><a id="id596470" class="indexterm"></a><a id="id596482" class="indexterm"></a><a id="id648867" class="indexterm"></a><div class="para">
Direct I/O is a feature of the file system whereby file reads and writes go directly from the applications to the storage device, bypassing the operating system read and write caches. Direct I/O is used only by applications (such as databases) that manage their own caches.
</div><div class="para">
An application invokes direct I/O by opening a file with the <code class="option">O_DIRECT</code> flag. Alternatively, GFS can attach a direct I/O attribute to a file, in which case direct I/O is used regardless of how the file is opened.
</div><div class="para">
When a file is opened with <code class="option">O_DIRECT</code>, or when a GFS direct I/O attribute is attached to a file, all I/O operations must be done in block-size multiples of 512 bytes. The memory being read from or written to must also be 512-byte aligned.
</div><div class="note"><div class="admonition_header"><h2>टीप</h2></div><div class="admonition"><div class="para">
Performing I/O through a memory mapping and also via direct I/O to the same file at the same time may result in the direct I/O being failed with an I/O error. This occurs because the page invalidation required for the direct I/O can race with a page fault generated through the mapping. This is a problem only when the memory mapped I/O and the direct I/O are both performed on the same node as each other, and to the same file at the same point in time. A workaround is to use file locking to ensure that memory mapped (i.e., page faults) and direct I/O do not occur simultaneously on the same file.
</div><div class="para">
The Oracle database, which is one of the main direct I/O using applications, does not memory map the files to which it uses direct I/O and thus is unaffected. In addition, writing to a file that is memory mapped will succeed, as expected, unless there are page faults in flight at that point in time. The <code class="command">mmap</code> system call on its own is safe when direct I/O is in use.
</div></div></div><div class="para">
One of the following methods can be used to enable direct I/O on a file:
</div><div class="itemizedlist"><ul><li class="listitem"><div class="para">
<code class="option">O_DIRECT</code>
</div></li><li class="listitem"><div class="para">
GFS file attribute
</div></li><li class="listitem"><div class="para">
GFS directory attribute
</div></li></ul></div><div class="section" id="s2-manage-odirect"><div class="titlepage"><div><div><h3 class="title" id="s2-manage-odirect">3.9.1. <code class="option">O_DIRECT</code></h3></div></div></div><a id="id648970" class="indexterm"></a><a id="id648989" class="indexterm"></a><a id="id649007" class="indexterm"></a><div class="para">
If an application uses the <code class="option">O_DIRECT</code> flag on an <code class="command">open()</code> system call, direct I/O is used for the opened file.
</div><div class="para">
To cause the <code class="option">O_DIRECT</code> flag to be defined with recent glibc libraries, define <code class="option">_GNU_SOURCE</code> at the beginning of a source file before any includes, or define it on the <span class="guilabel"><strong>cc</strong></span> line when compiling.
</div></div><div class="section" id="s2-manage-fileattribute"><div class="titlepage"><div><div><h3 class="title" id="s2-manage-fileattribute">3.9.2. GFS File Attribute</h3></div></div></div><a id="id649061" class="indexterm"></a><a id="id649077" class="indexterm"></a><a id="id649093" class="indexterm"></a><div class="para">
The <code class="command">gfs_tool</code> command can be used to assign (set) a direct I/O attribute flag, <code class="option">directio</code>, to a GFS file. The <code class="option">directio</code> flag can also be cleared.
</div><div class="para">
You can use the <code class="command">gfs_tool stat <em class="replaceable"><code>filename</code></em></code> to check what flags have been set for a GFS file. The output for this command includes a <code class="literal">Flags:</code> at the end of the display followed by a listing of the flags that are set for the indicated file.
</div><div class="simplesect" id="ss-manage-fa-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><div class="para">
<span class="application"><strong>Setting the <code class="option">directio</code> Flag</strong></span>
</div><pre class="screen">
gfs_tool setflag directio <em class="parameter"><code>File</code></em></pre><div class="para">
<span class="application"><strong>Clearing the <code class="option">directio</code> Flag</strong></span>
</div><pre class="screen">
gfs_tool clearflag directio <em class="parameter"><code>File</code></em></pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>File</code></em></span></dt><dd><div class="para">
Specifies the file where the <code class="option">directio</code> flag is assigned.
</div></dd></dl></div></div><div class="simplesect" id="ss-manage-fa-ex"><div class="titlepage"><div><div><h1 class="title">Example</h1></div></div></div><div class="para">
In this example, the command sets the <code class="option">directio</code> flag on the file named <code class="filename">datafile</code> in directory <code class="filename">/mnt/gfs</code>.
</div><pre class="screen">
gfs_tool setflag directio /mnt/gfs/datafile
</pre><div class="para">
The following command checks whether the <code class="option">directio</code> flag is set for <code class="filename">/mnt/gfs/datafile</code>. The output has been elided to show only the relevant information.
</div><pre class="screen">
[root@tng3-1 gfs]# <strong class="userinput"><code>gfs_tool stat /mnt/gfs/datafile</code></strong>
mh_magic = 0x01161970
...
Flags:
directio
</pre></div></div><div class="section" id="s2-manage-dirattribute"><div class="titlepage"><div><div><h3 class="title" id="s2-manage-dirattribute">3.9.3. GFS Directory Attribute</h3></div></div></div><a id="id649271" class="indexterm"></a><a id="id649287" class="indexterm"></a><a id="id649303" class="indexterm"></a><div class="para">
The <code class="command">gfs_tool</code> command can be used to assign (set) a direct I/O attribute flag, <code class="option">inherit_directio</code>, to a GFS directory. Enabling the <code class="option">inherit_directio</code> flag on a directory causes all newly created regular files in that directory to automatically inherit the <code class="option">directio</code> flag. Also, the <code class="option">inherit_directio</code> flag is inherited by any new subdirectories created in the directory. The <code class="option">inherit_directio</code> flag can also be cleared.
</div><div class="simplesect" id="ss-manage-da-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><div class="para">
<span class="application"><strong>Setting the <code class="option">inherit_directio</code> flag</strong></span>
</div><pre class="screen">
gfs_tool setflag inherit_directio <em class="parameter"><code>Directory</code></em></pre><div class="para">
<span class="application"><strong>Clearing the <code class="option">inherit_directio</code> flag</strong></span>
</div><pre class="screen">
gfs_tool clearflag inherit_directio <em class="parameter"><code>Directory</code></em></pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>Directory</code></em></span></dt><dd><div class="para">
Specifies the directory where the <code class="option">inherit_directio</code> flag is set.
</div></dd></dl></div></div><div class="simplesect" id="ss-manage-da-ex"><div class="titlepage"><div><div><h1 class="title">Example</h1></div></div></div><div class="para">
In this example, the command sets the <code class="option">inherit_directio</code> flag on the directory named <code class="filename">/mnt/gfs/data</code>.
</div><pre class="screen">
gfs_tool setflag inherit_directio /mnt/gfs/data
</pre><div class="para">
This command displays the flags that have been set for the <code class="filename">/mnt/gfs/data</code> directory. The full output has been truncated.
</div><pre class="screen">
[root@tng3-1 gfs]# <strong class="userinput"><code>gfs_tool stat /mnt/gfs/data</code></strong>
...
Flags:
inherit_directio
</pre></div></div></div><div class="section" id="s1-manage-data-journal"><div class="titlepage"><div><div><h2 class="title" id="s1-manage-data-journal">3.10. Data Journaling</h2></div></div></div><a id="id649470" class="indexterm"></a><a id="id649482" class="indexterm"></a><div class="para">
Ordinarily, GFS writes only metadata to its journal. File contents are subsequently written to disk by the kernel's periodic sync that flushes file system buffers. An <code class="command">fsync()</code> call on a file causes the file's data to be written to disk immediately. The call returns when the disk reports that all data is safely written.
</div><div class="para">
Data journaling can result in a reduced <code class="command">fsync()</code> time, especially for small files, because the file data is written to the journal in addition to the metadata. An <code class="command">fsync()</code> returns as soon as the data is written to the journal, which can be substantially faster than the time it takes to write the file data to the main file system.
</div><div class="para">
Applications that rely on <code class="command">fsync()</code> to sync file data may see improved performance by using data journaling. Data journaling can be enabled automatically for any GFS files created in a flagged directory (and all its subdirectories). Existing files with zero length can also have data journaling turned on or off.
</div><div class="para">
Using the <code class="command">gfs_tool</code> command, data journaling is enabled on a directory (and all its subdirectories) or on a zero-length file by setting the <code class="option">inherit_jdata</code> or <code class="option">jdata</code> attribute flags to the directory or file, respectively. The directory and file attribute flags can also be cleared.
</div><div class="simplesect" id="ss-manage-dj-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><div class="para">
<span class="application"><strong>Setting and Clearing the <code class="option">inherit_jdata</code> Flag</strong></span>
</div><pre class="screen">
gfs_tool setflag inherit_jdata <em class="parameter"><code>Directory</code></em>
gfs_tool clearflag inherit_jdata <em class="parameter"><code>Directory</code></em></pre><div class="para">
<span class="application"><strong>Setting and Clearing the <code class="option">jdata</code> Flag</strong></span>
</div><pre class="screen">
gfs_tool setflag jdata <em class="parameter"><code>File</code></em>
gfs_tool clearflag jdata <em class="parameter"><code>File</code></em></pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>Directory</code></em></span></dt><dd><div class="para">
Specifies the directory where the flag is set or cleared.
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>File</code></em></span></dt><dd><div class="para">
Specifies the zero-length file where the flag is set or cleared.
</div></dd></dl></div></div><div class="simplesect" id="ss-manage-dj-ex"><div class="titlepage"><div><div><h1 class="title">Examples</h1></div></div></div><div class="para">
This example shows setting the <code class="option">inherit_jdata</code> flag on a directory. All files created in the directory or any of its subdirectories will have the <code class="option">jdata</code> flag assigned automatically. Any data written to the files will be journaled. This example also shows the <code class="command">gfs_tool stat</code> command you can use to verify what flags are set for a directory; the output has been elided to show only the relevant information.
</div><pre class="screen">
[root@tng3-1]# <strong class="userinput"><code>gfs_tool setflag inherit_jdata /mnt/gfs/data</code></strong>
[root@tng3-1]# <strong class="userinput"><code>gfs_tool stat /mnt/gfs/data</code></strong>
...
Flags:
inherit_jdata
</pre><div class="para">
This example shows setting the <code class="option">jdata</code> flag on a file. The file must have a size of zero when you set this flag. Any data written to the file will be journaled. This example also shows the <code class="command">gfs_tool stat</code> command you can use to verify what flags are set for a file; the output has been elided to show only the relevant information.
</div><pre class="screen">
[root@tng3-1]# <strong class="userinput"><code>gfs_tool setflag jdata /mnt/gfs/datafile</code></strong>
[root@tng3-1]# <strong class="userinput"><code>gfs_tool stat /mnt/gfs/datafile</code></strong>
...
Flags:
jdata
</pre></div></div><div class="section" id="s1-manage-atimeconf"><div class="titlepage"><div><div><h2 class="title" id="s1-manage-atimeconf">3.11. Configuring <code class="command">atime</code> Updates</h2></div></div></div><a id="id649716" class="indexterm"></a><a id="id649731" class="indexterm"></a><a id="id649746" class="indexterm"></a><div class="para">
Each file inode and directory inode has three time stamps associated with it:
</div><div class="itemizedlist"><ul><li class="listitem"><div class="para">
<code class="command">ctime</code> — The last time the inode status was changed
</div></li><li class="listitem"><div class="para">
<code class="command">mtime</code> — The last time the file (or directory) data was modified
</div></li><li class="listitem"><div class="para">
<code class="command">atime</code> — The last time the file (or directory) data was accessed
</div></li></ul></div><div class="para">
If <code class="command">atime</code> updates are enabled as they are by default on GFS and other Linux file systems then every time a file is read, its inode needs to be updated.
</div><div class="para">
Because few applications use the information provided by <code class="command">atime</code>, those updates can require a significant amount of unnecessary write traffic and file-locking traffic. That traffic can degrade performance; therefore, it may be preferable to turn off <code class="command">atime</code> updates.
</div><div class="para">
Two methods of reducing the effects of <code class="command">atime</code> updating are available:
</div><div class="itemizedlist"><ul><li class="listitem"><div class="para">
Mount with <code class="command">noatime</code>
</div></li><li class="listitem"><div class="para">
Tune GFS <code class="command">atime</code> quantum
</div></li></ul></div><div class="section" id="s2-manage-mountnoatime"><div class="titlepage"><div><div><h3 class="title" id="s2-manage-mountnoatime">3.11.1. Mount with <code class="command">noatime</code></h3></div></div></div><a id="id649872" class="indexterm"></a><a id="id649894" class="indexterm"></a><a id="id649917" class="indexterm"></a><div class="para">
A standard Linux mount option, <code class="option">noatime</code>, can be specified when the file system is mounted, which disables <code class="command">atime</code> updates on that file system.
</div><div class="simplesect" id="ss-manage-noatime-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><pre class="screen">
mount <em class="parameter"><code>BlockDevice MountPoint</code></em> -o noatime
</pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>BlockDevice</code></em></span></dt><dd><div class="para">
Specifies the block device where the GFS file system resides.
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>MountPoint</code></em></span></dt><dd><div class="para">
Specifies the directory where the GFS file system should be mounted.
</div></dd></dl></div></div><div class="simplesect" id="ss-manage-noatime-ex"><div class="titlepage"><div><div><h1 class="title">Example</h1></div></div></div><div class="para">
In this example, the GFS file system resides on the <code class="filename">/dev/vg01/lvol0</code> and is mounted on directory <code class="filename">/gfs</code> with atime updates turned off.
</div><pre class="screen">
mount /dev/vg01/lvol0 /gfs -o noatime
</pre></div></div><div class="section" id="s2-manage-tuneatime"><div class="titlepage"><div><div><h3 class="title" id="s2-manage-tuneatime">3.11.2. Tune GFS <code class="command">atime</code> Quantum</h3></div></div></div><a id="id650046" class="indexterm"></a><a id="id650069" class="indexterm"></a><a id="id650092" class="indexterm"></a><div class="para">
When <code class="command">atime</code> updates are enabled, GFS (by default) only updates them once an hour. The time quantum is a tunable parameter that can be adjusted using the <code class="command">gfs_tool</code> command.
</div><div class="para">
Each GFS node updates the access time based on the difference between its system time and the time recorded in the inode. It is required that system clocks of all GFS nodes in a cluster be synchronized. If a node's system time is out of synchronization by a significant fraction of the tunable parameter, <code class="option">atime_quantum</code>, then <code class="command">atime</code> updates are written more frequently. Increasing the frequency of <code class="command">atime</code> updates may cause performance degradation in clusters with heavy work loads.
</div><div class="para">
To see the current values of the GFS tunable parameters, including <code class="literal">atime_quantum</code>, you can use the <code class="command">gfs_tool gettune</code>, as described in <a class="xref" href="#s1-manage-tunables">विभाग 3.5, “Displaying GFS Tunable Parameters”</a>. The default value for <code class="option">atime_quantum</code> is 3600 seconds.
</div><div class="para">
The <code class="command">gfs_tool <code class="option">settune</code></code> command is used to change the <code class="option">atime_quantum</code> parameter value. It must be set on each node and each time the file system is mounted. The setting is not persistent across unmounts.
</div><div class="simplesect" id="ss-manage-tuneatime-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><div class="para">
<span class="application"><strong>Changing the <code class="option">atime_quantum</code> Parameter Value</strong></span>
</div><pre class="screen">
gfs_tool settune <em class="parameter"><code>MountPoint</code></em> atime_quantum <em class="parameter"><code>Seconds</code></em></pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>MountPoint</code></em></span></dt><dd><div class="para">
Specifies the directory where the GFS file system is mounted.
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>Seconds</code></em></span></dt><dd><div class="para">
Specifies the update period in seconds.
</div></dd></dl></div></div><div class="simplesect" id="ss-manage-tuneatime-ex"><div class="titlepage"><div><div><h1 class="title">Example</h1></div></div></div><div class="para">
In this example, the <code class="command">atime</code> update period is set to once a day (86,400 seconds) for the GFS file system on mount point <code class="filename">/gfs</code>.
</div><pre class="screen">
gfs_tool settune /gfs atime_quantum 86400
</pre></div></div></div><div class="section" id="s1-manage-suspendfs"><div class="titlepage"><div><div><h2 class="title" id="s1-manage-suspendfs">3.12. Suspending Activity on a File System</h2></div></div></div><a id="id650289" class="indexterm"></a><a id="id650297" class="indexterm"></a><div class="para">
You can suspend write activity to a file system by using the <code class="command">gfs_tool <code class="option">freeze</code></code> command. Suspending write activity allows hardware-based device snapshots to be used to capture the file system in a consistent state. The <code class="command">gfs_tool <code class="option">unfreeze</code></code> command ends the suspension.
</div><div class="simplesect" id="ss-manage-suspendfs-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><div class="para">
<span class="application"><strong>Start Suspension</strong></span>
</div><pre class="screen">
gfs_tool freeze <em class="parameter"><code>MountPoint</code></em></pre><div class="para">
<span class="application"><strong>End Suspension</strong></span>
</div><pre class="screen">
<code class="command">gfs_tool unfreeze <em class="parameter"><code>MountPoint</code></em></code></pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>MountPoint</code></em></span></dt><dd><div class="para">
Specifies the file system.
</div></dd></dl></div></div><div class="simplesect" id="ss-manage-suspendfs-ex"><div class="titlepage"><div><div><h1 class="title">Examples</h1></div></div></div><div class="para">
This example suspends writes to file system <code class="filename">/gfs</code>.
</div><pre class="screen">
gfs_tool freeze /gfs
</pre><div class="para">
This example ends suspension of writes to file system <code class="filename">/gfs</code>.
</div><pre class="screen">
gfs_tool unfreeze /gfs
</pre></div></div><div class="section" id="s1-manage-displaystats"><div class="titlepage"><div><div><h2 class="title" id="s1-manage-displaystats">3.13. Displaying Extended GFS Information and Statistics</h2></div></div></div><a id="id650437" class="indexterm"></a><a id="id650449" class="indexterm"></a><div class="para">
You can use the <code class="command">gfs_tool</code> command to gather a variety of details about GFS. This section describes typical use of the <code class="command">gfs_tool</code> command for displaying space usage, statistics, and extended status.
</div><div class="para">
The <code class="command">gfs_tool</code> command provides additional action flags (options) not listed in this section. For more information about other <code class="command">gfs_tool</code> flags, refer to the <code class="command">gfs_tool</code> man page.
</div><div class="section" id="s2-manage-displayspace"><div class="titlepage"><div><div><h3 class="title" id="s2-manage-displayspace">3.13.1. Displaying GFS Space Usage</h3></div></div></div><a id="id650496" class="indexterm"></a><a id="id650508" class="indexterm"></a><div class="para">
You can use the <code class="option">df</code> flag of the <code class="command">gfs_tool</code> to display a space-usage summary of a given file system. The information is more detailed than a standard <code class="option">df</code>.
</div><div class="simplesect" id="ss-manage-displayspace-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><pre class="screen">
gfs_tool df <em class="parameter"><code>MountPoint</code></em></pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>MountPoint</code></em></span></dt><dd><div class="para">
Specifies the file system to which the action applies.
</div></dd></dl></div></div><div class="simplesect" id="ss-manage-displayspace-ex"><div class="titlepage"><div><div><h1 class="title">Example</h1></div></div></div><div class="para">
This example reports extended file system usage about file system <code class="filename">/mnt/gfs</code>.
</div><pre class="screen">
[root@ask-07 ~]# <strong class="userinput"><code>gfs_tool df /mnt/gfs</code></strong>
/gfs:
SB lock proto = "lock_dlm"
SB lock table = "ask_cluster:mydata1"
SB ondisk format = 1309
SB multihost format = 1401
Block size = 4096
Journals = 8
Resource Groups = 605
Mounted lock proto = "lock_dlm"
Mounted lock table = "ask_cluster:mydata1"
Mounted host data = "jid=0:id=786433:first=1"
Journal number = 0
Lock module flags = 0
Local flocks = FALSE
Local caching = FALSE
Oopses OK = FALSE
Type Total Used Free use%
------------------------------------------------------------------------
inodes 5 5 0 100%
metadata 78 15 63 19%
data 41924125 0 41924125 0%
</pre></div></div><div class="section" id="s1-manage-displaycounts"><div class="titlepage"><div><div><h3 class="title" id="s1-manage-displaycounts">3.13.2. Displaying GFS Counters</h3></div></div></div><a id="id650615" class="indexterm"></a><a id="id650627" class="indexterm"></a><div class="para">
You can use the <code class="option">counters</code> flag of the <code class="command">gfs_tool</code> to display statistics about a file system. If the <code class="option">-c</code> option is used, the <code class="command">gfs_tool</code> command continues to run, displaying statistics once per second.
</div><div class="note"><div class="admonition_header"><h2>टीप</h2></div><div class="admonition"><div class="para">
The majority of the GFS counters reflect the internal operation of the GFS file system and are for development purposes only.
</div></div></div><div class="para">
The <code class="command">gfs_tool counters</code> command displays the following statistics.
</div><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><code class="literal">locks</code></span></dt><dd><div class="para">
The number of <code class="literal">gfs_glock</code> structures that currently exist in gfs.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">locks held</code></span></dt><dd><div class="para">
The number of existing <code class="literal">gfs_glock</code> structures that are not in the <code class="literal">UNLOCKED</code> state.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">freeze count</code></span></dt><dd><div class="para">
A freeze count greater than 0 means the file system is frozen. A freeze count of 0 means the file system is not frozen. Each <code class="command">gfs_tool freeze</code> command increments this count. Each <code class="command">gfs_tool unfreeze</code> command decrements this count.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">incore inodes</code></span></dt><dd><div class="para">
The number of <code class="literal">gfs_inode</code> structures that currently exist in gfs.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">metadata buffers</code></span></dt><dd><div class="para">
The number of <code class="literal">gfs_bufdata</code> structures that currently exist in gfs.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">unlinked inodes</code></span></dt><dd><div class="para">
The <code class="literal">gfs_inoded</code> daemon links deleted inodes to a global list and cleans them up every 15 seconds (a period that is tunable). This number is the list length. It is related to the number of <code class="literal">gfs_unlinked</code> structures currently in gfs.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">quota IDs</code></span></dt><dd><div class="para">
The number of <code class="literal">gfs_quota_data</code> structures that currently exist in gfs.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">incore log buffers</code></span></dt><dd><div class="para">
The number of buffers in in-memory journal log (incore log), before they are flushed to disk.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">log space used</code></span></dt><dd><div class="para">
The the percentage of journal space used.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">meta header cache entries</code></span></dt><dd><div class="para">
The number of <code class="literal">gfs_meta_header_cache</code> structures that currently exist in gfs.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">glock dependencies</code></span></dt><dd><div class="para">
The number of <code class="literal">gfs_depend structures</code> that currently exist in gfs.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">glocks on reclaim list</code></span></dt><dd><div class="para">
The number of glocks on the reclaim list.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">log wraps</code></span></dt><dd><div class="para">
The number of times journal has wrapped around.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">outstanding LM calls</code></span></dt><dd><div class="para">
obsolete
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">outstanding BIO calls</code></span></dt><dd><div class="para">
obsolete
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">fh2dentry misses</code></span></dt><dd><div class="para">
The number of times an NFS call could not find a <code class="literal">dentry</code> structure in the cache.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">glocks reclaimed</code></span></dt><dd><div class="para">
The number of glocks which have been reclaimed.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">glock dq calls</code></span></dt><dd><div class="para">
The number of glocks released since the file system was mounted.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">glock prefetch calls</code></span></dt><dd><div class="para">
The number of glock prefetch calls.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">lm_lock calls</code></span></dt><dd><div class="para">
The number of times the lock manager has been contacted to obtain a lock.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">lm_unlock calls</code></span></dt><dd><div class="para">
The number of times the lock manager has been contacted to release a lock.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">lm callbacks</code></span></dt><dd><div class="para">
The number of times the lock manager has been contacted to change a lock state.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">address operations</code></span></dt><dd><div class="para">
The number of address space call operations (<code class="literal">readpage</code>, <code class="literal">writepage</code>, <code class="literal">directIO</code>, <code class="literal">prepare_write</code>, and <code class="literal">commit_write</code>)
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">dentry operations</code></span></dt><dd><div class="para">
The number of times a seek operation has been performed on the vfs <code class="literal">dentry</code> structure.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">export operations</code></span></dt><dd><div class="para">
The number of times a seek operation has been performed on the nfs <code class="literal">dentry</code> structure.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">file operations</code></span></dt><dd><div class="para">
The number of file operations that have been invoked (read, write, seek, etc).
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">inode operations</code></span></dt><dd><div class="para">
The number of inode operations that have been invoked (create, delete, symlink, etc.).
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">super operations</code></span></dt><dd><div class="para">
The number of super block operations.
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">vm operations</code></span></dt><dd><div class="para">
The number of times the <code class="command">mmap</code> function has been called. mmap call count
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">block I/O reads</code></span></dt><dd><div class="para">
obsolete
</div></dd><dt class="varlistentry"><span class="term"><code class="literal">block I/O writes</code></span></dt><dd><div class="para">
obsolete
</div></dd></dl></div><div class="simplesect" id="ss-manage-displaycounts-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><pre class="screen">
gfs_tool counters <em class="parameter"><code>MountPoint</code></em></pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>MountPoint</code></em></span></dt><dd><div class="para">
Specifies the file system to which the action applies.
</div></dd></dl></div></div><div class="simplesect" id="ss-manage-displaycounts-ex"><div class="titlepage"><div><div><h1 class="title">Example</h1></div></div></div><div class="para">
This example reports statistics about the file system mounted at <code class="filename">/mnt/gfs</code>.
</div><pre class="screen">
[root@tng3-1 gfs]# <strong class="userinput"><code>gfs_tool counters /mnt/gfs</code></strong>
locks 165
locks held 133
freeze count 0
incore inodes 34
metadata buffers 5
unlinked inodes 0
quota IDs 0
incore log buffers 0
log space used 0.05%
meta header cache entries 5
glock dependencies 5
glocks on reclaim list 0
log wraps 0
outstanding LM calls 0
outstanding BIO calls 0
fh2dentry misses 0
glocks reclaimed 345
glock nq calls 11632
glock dq calls 11596
glock prefetch calls 84
lm_lock calls 545
lm_unlock calls 237
lm callbacks 782
address operations 1075
dentry operations 374
export operations 0
file operations 1428
inode operations 1451
super operations 21239
vm operations 0
block I/O reads 0
block I/O writes 0
</pre></div></div><div class="section" id="s1-manage-displayexstat"><div class="titlepage"><div><div><h3 class="title" id="s1-manage-displayexstat">3.13.3. Displaying Extended Status</h3></div></div></div><a id="id651387" class="indexterm"></a><a id="id651399" class="indexterm"></a><div class="para">
You can use the <code class="option">stat</code> flag of the <code class="command">gfs_tool</code> to display extended status information about a GFS file.
</div><div class="note"><div class="admonition_header"><h2>टीप</h2></div><div class="admonition"><div class="para">
The information that the <code class="command">gfs_tool stat</code> command displays reflects internal file system information. This information is intended for development purposes only.
</div></div></div><div class="simplesect" id="ss-manage-displayexstat-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><pre class="screen">
gfs_tool stat <em class="parameter"><code>File</code></em></pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>File</code></em></span></dt><dd><div class="para">
Specifies the file from which to get information.
</div></dd></dl></div></div><div class="simplesect" id="ss-manage-displayexstat-ex"><div class="titlepage"><div><div><h1 class="title">Example</h1></div></div></div><div class="para">
This example reports extended file status about file <code class="filename">/gfs/datafile</code>.
</div><pre class="screen">
[root@tng3-1 gfs]# <strong class="userinput"><code>gfs_tool stat /gfs/datafile</code></strong>
mh_magic = 0x01161970
mh_type = 4
mh_generation = 3
mh_format = 400
mh_incarn = 1
no_formal_ino = 66
no_addr = 66
di_mode = 0600
di_uid = 0
di_gid = 0
di_nlink = 1
di_size = 503156
di_blocks = 124
di_atime = 1207672023
di_mtime = 1207672023
di_ctime = 1207672023
di_major = 0
di_minor = 0
di_rgrp = 17
di_goal_rgrp = 17
di_goal_dblk = 371
di_goal_mblk = 44
di_flags = 0x00000000
di_payload_format = 0
di_type = 1
di_height = 1
di_incarn = 0
di_pad = 0
di_depth = 0
di_entries = 0
no_formal_ino = 0
no_addr = 0
di_eattr = 0
di_reserved =
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00
</pre></div></div></div><div class="section" id="s1-manage-repairfs"><div class="titlepage"><div><div><h2 class="title" id="s1-manage-repairfs">3.14. Repairing a File System</h2></div></div></div><a id="id651516" class="indexterm"></a><a id="id651528" class="indexterm"></a><div class="para">
When nodes fail with the file system mounted, file system journaling allows fast recovery. However, if a storage device loses power or is physically disconnected, file system corruption may occur. (Journaling cannot be used to recover from storage subsystem failures.) When that type of corruption occurs, you can recover the GFS file system by using the <code class="command">gfs_fsck</code> command.
</div><div class="important"><div class="admonition_header"><h2>Important</h2></div><div class="admonition"><div class="para">
The <code class="command">gfs_fsck</code> command must be run only on a file system that is unmounted from all nodes.
</div></div></div><div class="important"><div class="admonition_header"><h2>Important</h2></div><div class="admonition"><div class="para">
You should not check a GFS file system at boot time with the <code class="command">gfs_fsck</code> command. The <code class="command">gfs_fsck</code> command can not determine at boot time whether the file system is mounted by another node in the cluster. You should run the <code class="command">gfs_fsck</code> command manually only after the system boots.
</div><div class="para">
To ensure that the <code class="command">gfs_fsck</code> command does not run on a GFS file system at boot time, modify the <code class="filename">/etc/fstab</code> file so that the final two columns for a GFS file system mount point show "0 0" rather than "1 1" (or any other numbers), as in the following example:
</div><pre class="screen">
/dev/VG12/lv_svr_home /svr_home gfs defaults,noatime,nodiratime,noquota 0 0
</pre></div></div><div class="note"><div class="admonition_header"><h2>Note</h2></div><div class="admonition"><div class="para">
The <code class="command">gfs_fsck</code> command has changed from previous releases of Red Hat GFS in the following ways:
</div><div class="itemizedlist"><ul><li class="listitem"><div class="para">
Pressing <span class="keycap"><strong>Ctrl</strong></span>+<span class="keycap"><strong>C</strong></span> while running the <code class="command">gfs_fsck</code> interrupts processing and displays a prompt asking whether you would like to abort the command, skip the rest of the current pass, or continue processing.
</div></li><li class="listitem"><div class="para">
You can increase the level of verbosity by using the <code class="option">-v</code> flag. Adding a second <code class="option">-v</code> flag increases the level again.
</div></li><li class="listitem"><div class="para">
You can decrease the level of verbosity by using the <code class="option">-q</code> flag. Adding a second <code class="option">-q</code> flag decreases the level again.
</div></li><li class="listitem"><div class="para">
The <code class="option">-n</code> option opens a file system as read-only and answers <strong class="userinput"><code>no</code></strong> to any queries automatically. The option provides a way of trying the command to reveal errors without actually allowing the <code class="command">gfs_fsck</code> command to take effect.
</div></li></ul></div><div class="para">
Refer to the <code class="command">gfs_fsck</code> man page, <code class="filename">gfs_fsck(8)</code>, for additional information about other command options.
</div></div></div><div class="para">
Running the <code class="command">gfs_fsck</code> command requires system memory above and beyond the memory used for the operating system and kernel. Each block of memory in the file system itself requires approximately one byte of additional memory. So to estimate the amount of memory you will need to run the <code class="command">gfs_fsck</code> command on your file system, divide the file system size (in bytes) by the block size.
</div><div class="para">
For example, for a GFS file system that is 16TB with a block size of 4K, divide 16TB by 4K:
</div><pre class="screen"> 17592186044416 / 4096 = 4294967296</pre><div class="para">
This file system requires approximately 4GB of free memory to run the <code class="command">gfs_fsck</code> command. Note that if the block size was 1K, running the <code class="command">gfs_fsck</code> command would require four times the memory, or 16GB.
</div><div class="simplesect" id="ss-manage-repairfs-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><pre class="screen">
gfs_fsck -y <em class="parameter"><code>BlockDevice</code></em></pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><code class="option">-y</code></span></dt><dd><div class="para">
The <code class="option">-y</code> flag causes all questions to be answered with <code class="computeroutput">yes</code>. With the <code class="option">-y</code> flag specified, the <code class="command">gfs_fsck</code> command does not prompt you for an answer before making changes.
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>BlockDevice</code></em></span></dt><dd><div class="para">
Specifies the block device where the GFS file system resides.
</div></dd></dl></div></div><div class="simplesect" id="ss-manage-repairfs-ex"><div class="titlepage"><div><div><h1 class="title">Example</h1></div></div></div><div class="para">
In this example, the GFS file system residing on block device <code class="filename">/dev/gfsvg/gfslv</code> is repaired. All queries to repair are automatically answered with <code class="computeroutput">yes</code>. Because this example uses the <code class="option">-v</code> (verbose) option, the sample output is extensive and repetitive lines have been elided.
</div><pre class="screen">
[root@tng3-1]# <strong class="userinput"><code>gfs_fsck -v -y /dev/gfsvg/gfslv</code></strong>
Initializing fsck
Initializing lists...
Initializing special inodes...
Validating Resource Group index.
Level 1 check.
92 resource groups found.
(passed)
Setting block ranges...
Creating a block list of size 9175040...
Clearing journals (this may take a while)Clearing journal 0
Clearing journal 1
Clearing journal 2
...
Clearing journal 10
Journals cleared.
Starting pass1
Checking metadata in Resource Group 0
Checking metadata in Resource Group 1
...
Checking metadata in Resource Group 91
Pass1 complete
Starting pass1b
Looking for duplicate blocks...
No duplicate blocks found
Pass1b complete
Starting pass1c
Looking for inodes containing ea blocks...
Pass1c complete
Starting pass2
Checking directory inodes.
Pass2 complete
Starting pass3
Marking root inode connected
Checking directory linkage.
Pass3 complete
Starting pass4
Checking inode reference counts.
Pass4 complete
Starting pass5
...
Updating Resource Group 92
Pass5 complete
Writing changes to disk
Syncing the device.
Freeing buffers.
</pre></div></div><div class="section" id="s1-manage-pathnames"><div class="titlepage"><div><div><h2 class="title" id="s1-manage-pathnames">3.15. Context-Dependent Path Names</h2></div></div></div><a id="id651875" class="indexterm"></a><a id="id651887" class="indexterm"></a><div class="para">
<em class="firstterm">Context-Dependent Path Names</em> (CDPNs) allow symbolic links to be created that point to variable destination files or directories. The variables are resolved to real files or directories each time an application follows the link. The resolved value of the link depends on the node or user following the link.
</div><div class="para">
CDPN variables can be used in any path name, not just with symbolic links. However, the CDPN variable name cannot be combined with other characters to form an actual directory or file name. The CDPN variable must be used alone as one segment of a complete path.
</div><div class="simplesect" id="ss-manage-pn-use"><div class="titlepage"><div><div><h1 class="title">Usage</h1></div></div></div><div class="para">
<span class="application"><strong>For a Normal Symbolic Link</strong></span>
</div><pre class="screen">
ln -s <em class="parameter"><code>Target</code></em> <em class="parameter"><code>LinkName</code></em>
</pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>Target</code></em></span></dt><dd><div class="para">
Specifies an existing file or directory on a file system.
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>LinkName</code></em></span></dt><dd><div class="para">
Specifies a name to represent the real file or directory on the other end of the link.
</div></dd></dl></div><div class="para">
<span class="application"><strong>For a Variable Symbolic Link</strong></span>
</div><pre class="screen">
ln -s <em class="parameter"><code>Variable</code></em> <em class="parameter"><code>LinkName</code></em>
</pre><div class="variablelist"><dl><dt class="varlistentry"><span class="term"><em class="parameter"><code>Variable</code></em></span></dt><dd><div class="para">
Specifies a special reserved name from a list of values (refer to <a class="xref" href="#tb-table-gfs-cdpn-varvalues">तक्ता 3.5, “CDPN <em class="parameter"><code>Variable</code></em> Values”</a>) to represent one of multiple existing files or directories. This string is not the name of an actual file or directory itself. (The real files or directories must be created in a separate step using names that correlate with the type of variable used.)
</div></dd><dt class="varlistentry"><span class="term"><em class="parameter"><code>LinkName</code></em></span></dt><dd><div class="para">
Specifies a name that will be seen and used by applications and will be followed to get to one of the multiple real files or directories. When <em class="parameter"><code>LinkName</code></em> is followed, the destination depends on the type of variable and the node or user doing the following.
</div></dd></dl></div><a id="id635698" class="indexterm"></a><a id="id635714" class="indexterm"></a><div class="table" id="tb-table-gfs-cdpn-varvalues"><h6>तक्ता 3.5. CDPN <em class="parameter"><code>Variable</code></em> Values</h6><div class="table-contents"><table summary="CDPN Variable Values" border="1"><colgroup><col width="29%" class="Variable" /><col width="71%" class="Description" /></colgroup><thead><tr><th>
Variable
</th><th>
Description
</th></tr></thead><tbody><tr><td>
<code class="command">@hostname</code>
</td><td>
This variable resolves to a real file or directory named with the hostname string produced by the output of the following command: <code class="command">echo `uname -n`</code>
</td></tr><tr><td>
<code class="command">@mach</code>
</td><td>
This variable resolves to a real file or directory name with the machine-type string produced by the output of the following command: <code class="command">echo `uname -m`</code>
</td></tr><tr><td>
<code class="command">@os</code>
</td><td>
This variable resolves to a real file or directory named with the operating-system name string produced by the output of the following command: <code class="command">echo `uname -s`</code>
</td></tr><tr><td>
<code class="command">@sys</code>
</td><td>
This variable resolves to a real file or directory named with the combined machine type and OS release strings produced by the output of the following command: <code class="command">echo `uname -m`_`uname -s`</code>
</td></tr><tr><td>
<code class="command">@uid</code>
</td><td>
This variable resolves to a real file or directory named with the user ID string produced by the output of the following command: <code class="command">echo `id -u`</code>
</td></tr><tr><td>
<code class="command">@gid</code>
</td><td>
This variable resolves to a real file or directory named with the group ID string produced by the output of the following command: <code class="command">echo `id -g`</code>
</td></tr></tbody></table></div></div><br class="table-break" /></div><div class="simplesect" id="ss-manage-pn-ex"><div class="titlepage"><div><div><h1 class="title">Example</h1></div></div></div><div class="para">
In this example, there are three nodes with hostnames <code class="filename">n01</code>, <code class="filename">n02</code> and <code class="filename">n03</code>. Applications on each node uses directory <code class="filename">/gfs/log/</code>, but the administrator wants these directories to be separate for each node. To do this, no actual log directory is created; instead, an <code class="command">@hostname</code> CDPN link is created with the name <code class="filename">log</code>. Individual directories <code class="filename">/gfs/n01/</code>, <code class="filename">/gfs/n02/</code>, and <code class="filename">/gfs/n03/</code> are created that will be the actual directories used when each node references <code class="filename">/gfs/log/</code>.
</div><pre class="screen">
n01# <strong class="userinput"><code>cd /gfs</code></strong>
n01# <strong class="userinput"><code>mkdir n01 n02 n03</code></strong>
n01# <strong class="userinput"><code>ln -s @hostname log</code></strong>
n01# <strong class="userinput"><code>ls -l /gfs</code></strong>
lrwxrwxrwx 1 root root 9 Apr 25 14:04 log -> @hostname/
drwxr-xr-x 2 root root 3864 Apr 25 14:05 n01/
drwxr-xr-x 2 root root 3864 Apr 25 14:06 n02/
drwxr-xr-x 2 root root 3864 Apr 25 14:06 n03/
n01# <strong class="userinput"><code>touch /gfs/log/fileA</code></strong>
n02# <strong class="userinput"><code>touch /gfs/log/fileB</code></strong>
n03# <strong class="userinput"><code>touch /gfs/log/fileC</code></strong>
n01# <strong class="userinput"><code>ls /gfs/log/</code></strong>
fileA
n02# <strong class="userinput"><code>ls /gfs/log/</code></strong>
fileB
n03# <strong class="userinput"><code>ls /gfs/log/</code></strong>
fileC
</pre></div></div><div class="section" id="s1-manage-gfswithdraw"><div class="titlepage"><div><div><h2 class="title" id="s1-manage-gfswithdraw">3.16. The GFS Withdraw Function</h2></div></div></div><a id="id636027" class="indexterm"></a><a id="id636035" class="indexterm"></a><div class="para">
The GFS <em class="firstterm">withdraw</em> function is a data integrity feature of GFS file systems in a cluster. If the GFS kernel module detects an inconsistency in a GFS file system following an I/O operation, the file system becomes unavailable to the cluster. The I/O operation stops and the system waits for further I/O operations to stop with an error, preventing further damage. When this occurs, you can stop any other services or applications manually, after which you can reboot and remount the GFS file system to replay the journals. If the problem persists, you can unmount the file system from all nodes in the cluster and perform file system recovery with the <code class="command">gfs_fsck</code> command. The GFS withdraw function is less severe than a kernel panic, which would cause another node to fence the node.
</div><div class="para">
An example of an inconsistency that would yield a GFS withdraw is an incorrect block count. When the GFS kernel module deletes a file from a file system, it systematically removes all the data and metadata blocks associated with that file. When it is done, it checks the block count. If the block count is not one (meaning all that is left is the disk inode itself), that indicates a file system inconsistency since the block count did not match the list of blocks found.
</div><div class="para">
You can override the GFS withdraw function by mounting the file system with the <code class="literal">-o errors=panic</code> option specified. When this option is specified, any errors that would normally cause the system to withdraw cause the system to panic instead. This stops the node's cluster communications, which causes the node to be fenced.
</div><div class="para">
Internally, the GFS2 withdraw function works by having the kernel send a message to the <code class="command">gfs_controld</code> daemon requesting withdraw. The <code class="command">gfs_controld</code> daemon runs the <code class="command">dmsetup</code> program to place the device mapper error target underneath the filesystem preventing further access to the block device. It then tells the kernel that this has been completed. This is the reason for the GFS2 support requirement to always use a CLVM device under GFS2, since otherwise it is not possible to insert a device mapper target.
</div><div class="para">
The purpose of the device mapper error target is to ensure that all future I/O operations will result in an I/O error that will allow the filesystem to be unmounted in an orderly fashion. As a result, when the withdraw occurs, it is normal to see a number of I/O errors from the device mapper device reported in the system logs.
</div><div class="para">
Occasionally, the withdraw may fail if it is not possible for the <code class="command">dmsetup</code> program to insert the error target as requested. This can happen if there is a shortage of memory at the point of the withdraw and memory cannot be reclaimed due to the problem that triggered the withdraw in the first place.
</div><div class="para">
A withdraw does not always mean that there is an error in GFS2. Sometimes the withdraw function can be triggered by device I/O errors relating to the underlying block device. It is highly recommended to check the logs to see if that is the case if a withdraw occurs.
</div></div></div><div xml:lang="mr-IN" class="appendix" id="appe-Publican-Revision_History" lang="mr-IN"><div class="titlepage"><div><div><h1 class="title">Revision History</h1></div></div></div><div class="para">
<div class="revhistory"><table border="0" width="100%" summary="Revision history"><tr><th align="left" valign="top" colspan="3"><strong>आवृत्ती हतिहास</strong></th></tr><tr><td align="left">आवृत्ती 6.0-3</td><td align="left">Tue Jan 24 2012</td><td align="left"><span class="author"><span class="firstname">Steven</span> <span class="surname">Levine</span></span></td></tr><tr><td align="left" colspan="3">
<table border="0" summary="Simple list" class="simplelist"><tr><td>Release for Red Hat Enterprise Linux 5.8</td></tr></table>
</td></tr><tr><td align="left">आवृत्ती 6.0-2</td><td align="left">Thu Dec 15 2011</td><td align="left"><span class="author"><span class="firstname">Steven</span> <span class="surname">Levine</span></span></td></tr><tr><td align="left" colspan="3">
<table border="0" summary="Simple list" class="simplelist"><tr><td>Beta release of Red Hat Enterprise Linux 5.8</td></tr></table>
</td></tr><tr><td align="left">आवृत्ती 6.0-1</td><td align="left">Thu Nov 10 2011</td><td align="left"><span class="author"><span class="firstname">Steven</span> <span class="surname">Levine</span></span></td></tr><tr><td align="left" colspan="3">
<table border="0" summary="Simple list" class="simplelist"><tr><td>Resolves: #758843</td></tr><tr><td> Notes CLVM requirement for clustered environment. </td></tr></table>
<table border="0" summary="Simple list" class="simplelist"><tr><td>Resolves: #736157</td></tr><tr><td> Adds note warning not to check a GFS file system at boot time. </td></tr></table>
</td></tr><tr><td align="left">आवृत्ती 5.0-1</td><td align="left">Thu Jul 21 2011</td><td align="left"><span class="author"><span class="firstname">Steven</span> <span class="surname">Levine</span></span></td></tr><tr><td align="left" colspan="3">
<table border="0" summary="Simple list" class="simplelist"><tr><td>Resolves: #458880</td></tr><tr><td> Adds note about using file locking to ensure that memory mapped and direct I/O do not occur simultaneously on the same file. </td></tr></table>
<table border="0" summary="Simple list" class="simplelist"><tr><td>Resolves: #676133</td></tr><tr><td> Clarifies section on the withdraw function. </td></tr></table>
</td></tr><tr><td align="left">आवृत्ती 4.0-1</td><td align="left">Thu Dec 23 2010</td><td align="left"><span class="author"><span class="firstname">Steven</span> <span class="surname">Levine</span></span></td></tr><tr><td align="left" colspan="3">
<table border="0" summary="Simple list" class="simplelist"><tr><td>Resolves: #661520</td></tr><tr><td>Updates information about maximum file system size.</td></tr></table>
<table border="0" summary="Simple list" class="simplelist"><tr><td>Resolves: #667552</td></tr><tr><td>Adds note to overview about issuing operations on one directory from more than one node at the same time.</td></tr></table>
</td></tr><tr><td align="left">आवृत्ती 3.0-2</td><td align="left">Tue Aug 3 2010</td><td align="left"><span class="author"><span class="firstname">Steven</span> <span class="surname">Levine</span></span></td></tr><tr><td align="left" colspan="3">
<table border="0" summary="Simple list" class="simplelist"><tr><td>Resolves: #562251</td></tr><tr><td>Adds information about the <code class="literal">localflocks</code> mount option and when it may be required.</td></tr></table>
</td></tr><tr><td align="left">आवृत्ती 3.0-1</td><td align="left">Thu Mar 18 2010</td><td align="left"><span class="author"><span class="firstname">Steven</span> <span class="surname">Levine</span></span></td></tr><tr><td align="left" colspan="3">
<table border="0" summary="Simple list" class="simplelist"><tr><td>Resolves: #568179</td></tr><tr><td>Adds note clarifying support policy for single-node system.</td></tr></table>
<table border="0" summary="Simple list" class="simplelist"><tr><td>Resolves: #562199</td></tr><tr><td>Adds note clarifying 16-node limitation.</td></tr></table>
<table border="0" summary="Simple list" class="simplelist"><tr><td>Resolves: #515348</td></tr><tr><td>Documents new -o errors mount option.</td></tr></table>
<table border="0" summary="Simple list" class="simplelist"><tr><td>Resolves: #573750</td></tr><tr><td>Documents memory requirements for gfs_fsck.</td></tr></table>
<table border="0" summary="Simple list" class="simplelist"><tr><td>Resolves: #574462</td></tr><tr><td>Clarifies issue of gfs requiring CLVM for Red Hat support.</td></tr></table>
</td></tr><tr><td align="left">आवृत्ती 2.0-1</td><td align="left">Tue Aug 18 2009</td><td align="left"><span class="author"><span class="firstname">Steven</span> <span class="surname">Levine</span></span></td></tr><tr><td align="left" colspan="3">
<table border="0" summary="Simple list" class="simplelist"><tr><td>Resolves: #515807</td></tr><tr><td>Adds note clarifying that you cannot reduce the size of an existing file system.</td></tr></table>
<table border="0" summary="Simple list" class="simplelist"><tr><td>Resolves: #480002</td></tr><tr><td>Adds caveat about unmounting a file system manually if you mounted it manually. </td></tr></table>
<table border="0" summary="Simple list" class="simplelist"><tr><td>Resolves: #458604</td></tr><tr><td>Adds section on GFS withdraw function. </td></tr></table>
</td></tr><tr><td align="left">आवृत्ती 1.0-1</td><td align="left">Thu Jan 29 2009</td><td align="left"><span class="author"><span class="firstname"></span> <span class="surname"></span></span></td></tr><tr><td align="left" colspan="3">
<table border="0" summary="Simple list" class="simplelist"><tr><td></td></tr></table>
</td></tr></table></div>
</div></div><div class="index" id="id339920"><div class="titlepage"><div><div><h2 class="title">इंडेक्स्</h2></div></div></div><div class="index"><div class="indexdiv"><h3>A</h3><dl><dt>adding journals to a file system, <a class="indexterm" href="#s1-manage-addjournalfs">Adding Journals to a File System</a></dt><dt>atime, configuring updates, <a class="indexterm" href="#s1-manage-atimeconf">Configuring atime Updates</a></dt><dd><dl><dt>mounting with noatime , <a class="indexterm" href="#s2-manage-mountnoatime">Mount with noatime</a></dt><dt>tuning atime quantum, <a class="indexterm" href="#s2-manage-tuneatime">Tune GFS atime Quantum</a></dt></dl></dd><dt>audience, <a class="indexterm" href="#s1-intro-audience-GFS">Audience</a></dt></dl></div><div class="indexdiv"><h3>C</h3><dl><dt>CDPN variable values table, <a class="indexterm" href="#ss-manage-pn-use">Usage</a></dt><dt>configuration, before, <a class="indexterm" href="#s1-ov-preconfig-GFS">Before Setting Up GFS</a></dt><dt>configuration, initial, <a class="indexterm" href="#ch-config">Getting Started</a></dt><dd><dl><dt>prerequisite tasks, <a class="indexterm" href="#s1-config-prereq">Prerequisite Tasks</a></dt></dl></dd><dt>creating a file system, <a class="indexterm" href="#s1-manage-makefs">Creating a File System</a></dt></dl></div><div class="indexdiv"><h3>D</h3><dl><dt>data journaling, <a class="indexterm" href="#s1-manage-data-journal">Data Journaling</a></dt><dt>direct I/O, <a class="indexterm" href="#s1-manage-direct-io">Direct I/O</a></dt><dd><dl><dt>directory attribute, <a class="indexterm" href="#s2-manage-dirattribute">GFS Directory Attribute</a></dt><dt>file attribute, <a class="indexterm" href="#s2-manage-fileattribute">GFS File Attribute</a></dt><dt>O_DIRECT , <a class="indexterm" href="#s2-manage-odirect">O_DIRECT</a></dt></dl></dd><dt>displaying extended GFS information and statistics, <a class="indexterm" href="#s1-manage-displaystats">Displaying Extended GFS Information and Statistics</a></dt><dt>displaying GFS counters, <a class="indexterm" href="#s1-manage-displaycounts">Displaying GFS Counters</a></dt><dt>displaying GFS extended status, <a class="indexterm" href="#s1-manage-displayexstat">Displaying Extended Status</a></dt><dt>displaying GFS space usage, <a class="indexterm" href="#s2-manage-displayspace">Displaying GFS Space Usage</a></dt><dt>DLM (Distributed Lock Manager), <a class="indexterm" href="#s1-ov-newfeatures-GFS">New and Changed Features</a></dt></dl></div><div class="indexdiv"><h3>F</h3><dl><dt>features, new and changed, <a class="indexterm" href="#s1-ov-newfeatures-GFS">New and Changed Features</a></dt><dt>feedback, <a class="indexterm" href="#s1-intro-feedback-GFS">Feedback</a></dt><dt>file system</dt><dd><dl><dt>adding journals, <a class="indexterm" href="#s1-manage-addjournalfs">Adding Journals to a File System</a></dt><dt>atime, configuring updates, <a class="indexterm" href="#s1-manage-atimeconf">Configuring atime Updates</a></dt><dd><dl><dt>mounting with noatime , <a class="indexterm" href="#s2-manage-mountnoatime">Mount with noatime</a></dt><dt>tuning atime quantum, <a class="indexterm" href="#s2-manage-tuneatime">Tune GFS atime Quantum</a></dt></dl></dd><dt>context-dependent path names (CDPNs), <a class="indexterm" href="#s1-manage-pathnames">Context-Dependent Path Names</a></dt><dt>creating, <a class="indexterm" href="#s1-manage-makefs">Creating a File System</a></dt><dt>data journaling, <a class="indexterm" href="#s1-manage-data-journal">Data Journaling</a></dt><dt>direct I/O, <a class="indexterm" href="#s1-manage-direct-io">Direct I/O</a></dt><dd><dl><dt>directory attribute, <a class="indexterm" href="#s2-manage-dirattribute">GFS Directory Attribute</a></dt><dt>file attribute, <a class="indexterm" href="#s2-manage-fileattribute">GFS File Attribute</a></dt><dt>O_DIRECT , <a class="indexterm" href="#s2-manage-odirect">O_DIRECT</a></dt></dl></dd><dt>growing, <a class="indexterm" href="#s1-manage-growfs">Growing a File System</a></dt><dt>mounting, <a class="indexterm" href="#s1-manage-mountfs">Mounting a File System</a>, <a class="indexterm" href="#s1-mount-considerations">Special Considerations when Mounting GFS File Systems</a></dt><dt>quota management, <a class="indexterm" href="#s1-manage-quota">GFS Quota Management</a></dt><dd><dl><dt>disabling/enabling quota accounting, <a class="indexterm" href="#s2-manage-quotaaccount">Disabling/Enabling Quota Accounting</a></dt><dt>disabling/enabling quota enforcement, <a class="indexterm" href="#s2-manage-enablequota">Disabling/Enabling Quota Enforcement</a></dt><dt>displaying quota limits, <a class="indexterm" href="#s2-manage-displayquota">Displaying Quota Limits and Usage</a></dt><dt>setting quotas, <a class="indexterm" href="#s2-manage-setquota">Setting Quotas</a></dt><dt>synchronizing quotas, <a class="indexterm" href="#s2-manage-synchquota">Synchronizing Quotas</a></dt></dl></dd><dt>repairing, <a class="indexterm" href="#s1-manage-repairfs">Repairing a File System</a></dt><dt>suspending activity, <a class="indexterm" href="#s1-manage-suspendfs">Suspending Activity on a File System</a></dt><dt>unmounting, <a class="indexterm" href="#s1-manage-unmountfs">Unmounting a File System</a>, <a class="indexterm" href="#s1-mount-considerations">Special Considerations when Mounting GFS File Systems</a></dt></dl></dd></dl></div><div class="indexdiv"><h3>G</h3><dl><dt>GFS</dt><dd><dl><dt>atime, configuring updates, <a class="indexterm" href="#s1-manage-atimeconf">Configuring atime Updates</a></dt><dd><dl><dt>mounting with noatime , <a class="indexterm" href="#s2-manage-mountnoatime">Mount with noatime</a></dt><dt>tuning atime quantum, <a class="indexterm" href="#s2-manage-tuneatime">Tune GFS atime Quantum</a></dt></dl></dd><dt>direct I/O, <a class="indexterm" href="#s1-manage-direct-io">Direct I/O</a></dt><dd><dl><dt>directory attribute, <a class="indexterm" href="#s2-manage-dirattribute">GFS Directory Attribute</a></dt><dt>file attribute, <a class="indexterm" href="#s2-manage-fileattribute">GFS File Attribute</a></dt><dt>O_DIRECT , <a class="indexterm" href="#s2-manage-odirect">O_DIRECT</a></dt></dl></dd><dt>displaying counters, <a class="indexterm" href="#s1-manage-displaycounts">Displaying GFS Counters</a></dt><dt>displaying extended information and statistics, <a class="indexterm" href="#s1-manage-displaystats">Displaying Extended GFS Information and Statistics</a></dt><dt>displaying extended status, <a class="indexterm" href="#s1-manage-displayexstat">Displaying Extended Status</a></dt><dt>displaying space usage, <a class="indexterm" href="#s2-manage-displayspace">Displaying GFS Space Usage</a></dt><dt>managing, <a class="indexterm" href="#ch-manage">Managing GFS</a></dt><dt>quota management, <a class="indexterm" href="#s1-manage-quota">GFS Quota Management</a></dt><dd><dl><dt>disabling/enabling quota accounting, <a class="indexterm" href="#s2-manage-quotaaccount">Disabling/Enabling Quota Accounting</a></dt><dt>disabling/enabling quota enforcement, <a class="indexterm" href="#s2-manage-enablequota">Disabling/Enabling Quota Enforcement</a></dt><dt>displaying quota limits, <a class="indexterm" href="#s2-manage-displayquota">Displaying Quota Limits and Usage</a></dt><dt>setting quotas, <a class="indexterm" href="#s2-manage-setquota">Setting Quotas</a></dt><dt>synchronizing quotas, <a class="indexterm" href="#s2-manage-synchquota">Synchronizing Quotas</a></dt></dl></dd><dt>withdraw function, <a class="indexterm" href="#s1-manage-gfswithdraw">The GFS Withdraw Function</a></dt></dl></dd><dt>GFS file system maximum size, <a class="indexterm" href="#ch-overview-GFS">GFS Overview</a>, <a class="indexterm" href="#s1-ov-preconfig-GFS">Before Setting Up GFS</a></dt><dt>GFS software components, <a class="indexterm" href="#s1-ov-subsystems-GFS">GFS Software Components</a></dt><dt>GFS software components table, <a class="indexterm" href="#s1-ov-subsystems-GFS">GFS Software Components</a></dt><dt>GFS-specific options for adding journals table, <a class="indexterm" href="#ss-manage-addjournal-complete">Complete Usage</a></dt><dt>GFS-specific options for expanding file systems table, <a class="indexterm" href="#ss-manage-growfs-complete">Complete Usage</a></dt><dt>gfs_mkfs command options table, <a class="indexterm" href="#ss-mkfs-opts">Complete Options</a></dt><dt>growing a file system, <a class="indexterm" href="#s1-manage-growfs">Growing a File System</a></dt><dt>GULM (Grand Unified Lock Manager), <a class="indexterm" href="#s1-ov-newfeatures-GFS">New and Changed Features</a></dt></dl></div><div class="indexdiv"><h3>I</h3><dl><dt>initial tasks</dt><dd><dl><dt>setup, initial, <a class="indexterm" href="#s1-config-tasks">Initial Setup Tasks</a></dt></dl></dd><dt>introduction, <a class="indexterm" href="#ch-intro-GFS">Introduction</a></dt><dd><dl><dt>audience, <a class="indexterm" href="#s1-intro-audience-GFS">Audience</a></dt></dl></dd></dl></div><div class="indexdiv"><h3>M</h3><dl><dt>managing GFS, <a class="indexterm" href="#ch-manage">Managing GFS</a></dt><dt>maximum size, GFS file system, <a class="indexterm" href="#ch-overview-GFS">GFS Overview</a>, <a class="indexterm" href="#s1-ov-preconfig-GFS">Before Setting Up GFS</a></dt><dt>mount table, <a class="indexterm" href="#ss-gfs-mount-complete">Complete Usage</a></dt><dt>mounting a file system, <a class="indexterm" href="#s1-manage-mountfs">Mounting a File System</a>, <a class="indexterm" href="#s1-mount-considerations">Special Considerations when Mounting GFS File Systems</a></dt></dl></div><div class="indexdiv"><h3>O</h3><dl><dt>overview, <a class="indexterm" href="#ch-overview-GFS">GFS Overview</a></dt><dd><dl><dt>configuration, before, <a class="indexterm" href="#s1-ov-preconfig-GFS">Before Setting Up GFS</a></dt><dt>economy, <a class="indexterm" href="#s1-ov-perform-GFS">Performance, Scalability, and Economy</a></dt><dt>features, new and changed, <a class="indexterm" href="#s1-ov-newfeatures-GFS">New and Changed Features</a></dt><dt>GFS software components, <a class="indexterm" href="#s1-ov-subsystems-GFS">GFS Software Components</a></dt><dt>performance, <a class="indexterm" href="#s1-ov-perform-GFS">Performance, Scalability, and Economy</a></dt><dt>scalability, <a class="indexterm" href="#s1-ov-perform-GFS">Performance, Scalability, and Economy</a></dt></dl></dd></dl></div><div class="indexdiv"><h3>P</h3><dl><dt>parameters, GFS tunable, <a class="indexterm" href="#s1-manage-tunables">Displaying GFS Tunable Parameters</a></dt><dt>path names, context-dependent (CDPNs), <a class="indexterm" href="#s1-manage-pathnames">Context-Dependent Path Names</a></dt><dt>preface (पहा introduction)</dt><dt>prerequisite tasks</dt><dd><dl><dt>configuration, initial, <a class="indexterm" href="#s1-config-prereq">Prerequisite Tasks</a></dt></dl></dd></dl></div><div class="indexdiv"><h3>Q</h3><dl><dt>quota management, <a class="indexterm" href="#s1-manage-quota">GFS Quota Management</a></dt><dd><dl><dt>disabling/enabling quota accounting, <a class="indexterm" href="#s2-manage-quotaaccount">Disabling/Enabling Quota Accounting</a></dt><dt>disabling/enabling quota enforcement, <a class="indexterm" href="#s2-manage-enablequota">Disabling/Enabling Quota Enforcement</a></dt><dt>displaying quota limits, <a class="indexterm" href="#s2-manage-displayquota">Displaying Quota Limits and Usage</a></dt><dt>setting quotas, <a class="indexterm" href="#s2-manage-setquota">Setting Quotas</a></dt><dt>synchronizing quotas, <a class="indexterm" href="#s2-manage-synchquota">Synchronizing Quotas</a></dt></dl></dd></dl></div><div class="indexdiv"><h3>R</h3><dl><dt>repairing a file system, <a class="indexterm" href="#s1-manage-repairfs">Repairing a File System</a></dt></dl></div><div class="indexdiv"><h3>S</h3><dl><dt>setup, initial</dt><dd><dl><dt>initial tasks, <a class="indexterm" href="#s1-config-tasks">Initial Setup Tasks</a></dt></dl></dd><dt>suspending activity on a file system, <a class="indexterm" href="#s1-manage-suspendfs">Suspending Activity on a File System</a></dt><dt>system hang at unmount, <a class="indexterm" href="#s1-mount-considerations">Special Considerations when Mounting GFS File Systems</a></dt></dl></div><div class="indexdiv"><h3>T</h3><dl><dt>tables</dt><dd><dl><dt>CDPN variable values, <a class="indexterm" href="#ss-manage-pn-use">Usage</a></dt><dt>GFS software components, <a class="indexterm" href="#s1-ov-subsystems-GFS">GFS Software Components</a></dt><dt>GFS-specific options for adding journals, <a class="indexterm" href="#ss-manage-addjournal-complete">Complete Usage</a></dt><dt>GFS-specific options for expanding file systems, <a class="indexterm" href="#ss-manage-growfs-complete">Complete Usage</a></dt><dt>gfs_mkfs command options, <a class="indexterm" href="#ss-mkfs-opts">Complete Options</a></dt><dt>mount options, <a class="indexterm" href="#ss-gfs-mount-complete">Complete Usage</a></dt></dl></dd><dt>tunable parameters, GFS, <a class="indexterm" href="#s1-manage-tunables">Displaying GFS Tunable Parameters</a></dt></dl></div><div class="indexdiv"><h3>U</h3><dl><dt>unmount, system hang, <a class="indexterm" href="#s1-mount-considerations">Special Considerations when Mounting GFS File Systems</a></dt><dt>unmounting a file system, <a class="indexterm" href="#s1-manage-unmountfs">Unmounting a File System</a>, <a class="indexterm" href="#s1-mount-considerations">Special Considerations when Mounting GFS File Systems</a></dt></dl></div><div class="indexdiv"><h3>W</h3><dl><dt>withdraw function, GFS, <a class="indexterm" href="#s1-manage-gfswithdraw">The GFS Withdraw Function</a></dt></dl></div></div></div></div></body></html>
distrib
>
Scientific%20Linux
>
5x
>
x86_64
>
by-pkgid
>
5f44a404c26cf55f904af12f6a7b0b49
>
files
>
128
