<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>vfs_preopen</title><link rel="stylesheet" href="../samba.css" type="text/css"><meta name="generator" content="DocBook XSL Stylesheets V1.75.2"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="refentry" title="vfs_preopen"><a name="vfs_preopen.8"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>vfs_preopen — Hide read latencies for applications reading numbered files</p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><div class="cmdsynopsis"><p><code class="literal">vfs objects = preopen</code></p></div></div><div class="refsect1" title="DESCRIPTION"><a name="id266339"></a><h2>DESCRIPTION</h2><p>This VFS module is part of the <a class="citerefentry" href="samba.7.html"><span class="citerefentry"><span class="refentrytitle">samba</span>(7)</span></a> suite.</p><p>This module assists applications that want to read numbered files in sequence with very strict latency requirements. One area where this happens in video streaming applications that want to read one file per frame.</p><p>When you use this module, a number of helper processes is started that speculatively open files and read a number of bytes to prime the file system cache, so that later on when the real application's request comes along, no disk access is necessary.</p><p>This module is stackable.</p></div><div class="refsect1" title="OPTIONS"><a name="id266829"></a><h2>OPTIONS</h2><div class="variablelist"><dl><dt><span class="term">preopen:names = /pattern/</span></dt><dd><p> preopen:names specifies the file name pattern which should trigger the preopen helpers to do their work. We assume that the files are numbered incrementally. So if your file names are numbered FRAME00000.frm FRAME00001.frm and so on you would list them as <code class="literal">preopen:names=/FRAME*.frm/</code> </p></dd><dt><span class="term">preopen:num_bytes = BYTES</span></dt><dd><p> Specifies the number of bytes the helpers should speculatively read, defaults to 1. </p></dd><dt><span class="term">preopen:helpers = NUM-PROCS</span></dt><dd><p> Number of forked helper processes, defaults to 1. </p></dd><dt><span class="term">preopen:queuelen = NUM-FILES</span></dt><dd><p> Number of files that should be speculatively opened. Defaults to the 10 subsequent files. </p></dd></dl></div></div><div class="refsect1" title="VERSION"><a name="id265697"></a><h2>VERSION</h2><p>This man page is correct for version 3.3 of the Samba suite. </p></div><div class="refsect1" title="AUTHOR"><a name="id265707"></a><h2>AUTHOR</h2><p>The original Samba software and related utilities were created by Andrew Tridgell. Samba is now developed by the Samba Team as an Open Source project similar to the way the Linux kernel is developed.</p><p>The PREOPEN VFS module was created with contributions from Volker Lendecke and the developers at IBM. </p></div></div></body></html>
distrib
>
Scientific%20Linux
>
5x
>
x86_64
>
by-pkgid
>
56f2e61f0be2eed5aa0803f74f28044c
>
files
>
351
