Description:

Linux allows you to add and remove SCSI devices without rebooting by
using the echo "scsi add-single-device H C I L" > /proc/scsi/scsi
command (H = host, C = channel, I = SCSI ID, L = SCSI LUN). The
remove-single-device command works similarily.

Note, however, that the SCSI bus was NOT designed for hot-plugging, so
you might be out of luck ... And you have to be sure, that termination
is OK. All filesystems on a device have to be unmounted before
disconnecting it or powering it down.