ISCSID(8)						      System Manager's Manual							 ISCSID(8)

NAME

       iscsid - establish iSCSI connections

SYNOPSIS

       iscsid [ -b bindingfile ] [ -d ] [ -f configfile ] [ -l basedir ] [ -m mode ] [ -n ]

DESCRIPTION

       iscsid establishes connections with iSCSI targets defined in /etc/iscsi.conf.

       Once the Linux iSCSI driver is activated, a discovery process for iSCSI storage devices will proceed as follows:

       -      The  iSCSI  daemon requests available iSCSI targets from the iSCSI target, and passes the information discovered to the iSCSI kernel
	      module.

       -      The iSCSI kernel module establishes connections to the targets.

       -      Linux queries targets for device information.

       -      Linux creates a mapping from SCSI device nodes to iSCSI targets.

       iscsid should be started after networking is configured and stopped after all iSCSI devices have been unmounted.

       Warning: Data corruption can occur if you do not unmount iSCSI devices before disabling network interfaces!

DEVICE NAMES

       Because Linux assigns SCSI device nodes dynamically whenever a SCSI logical unit is detected, the mapping from device nodes (e.g  /dev/sda,
       /dev/sdb) to iSCSI targets and logical units may vary.

       Variations  in  process scheduling and network delay may result in iSCSI targets being mapped to different SCSI device nodes every time the
       driver is started.  Because of this variability, configuring applications or operating system utilities to use  the  standard  SCSI  device
       nodes to access iSCSI devices may result in SCSI commands being sent to the wrong target or logical unit.

       To  provide  a more reliable namespace, the iSCSI driver will scan the system to determine the mapping from SCSI device nodes to iSCSI tar-
       gets, and then create a tree of directories and symbolic links under /dev/iscsi to make it easier to use a particular iSCSI target's  logi-
       cal units.

TARGET BINDINGS

       The  iSCSI  driver  automatically maintains a bindings file /var/iscsi/bindings.  This file contains persistent bindings to ensure that the
       same iSCSI bus and target id number are used for every iSCSI session to a particular iSCSI TargetName, no matter how many times the  driver
       is restarted.

       This feature ensures that the SCSI numbers in the device symlinks described above will always map to the same iSCSI target.

       Note  that  because  of	the  way  Linux dynamically allocates SCSI device nodes as SCSI devices are found, the driver does not and can not
       ensure that any particular SCSI device node (e.g. /dev/sda) will always map to the same iSCSI TargetName.  The symlinks	described  in  the
       section	on  Device  Names  are intended to provide a persistent device mapping for use by applications and fstab files, and should be used
       instead of direct references to particular SCSI device nodes.

       If the bindings file grows too large, lines for targets that no longer exist may be manually removed by editing the file.   Manual  editing
       should not normally be needed, since the driver can maintain up to 65535 different bindings.

OPTIONS

       -b bindingfile
	      Specify an alternative bindings file instead of /var/iscsi/bindings, which is the default.

       -d     Turns on debug mode.  Each occurence of -d will increment the debug level by one.  The default is zero (off).

       -f configfile
	      Specify an alternative configuration file instead of /etc/iscsi.conf, which is the default.

       -l basedir
	      Specify  the base directory under which to build a tree of directories containing symlinks to SCSI device nodes, in a manner similar
	      to the devfs Linux kernel option.  Using these symlinks hides variations in the mapping from SCSI device nodes  to  SCSI	device	id
	      numbers.

       -m mode
	      Specify the directory permission mode (in octal) to use when creating directories.

       -n     Avoid auto-backgrounding.

       -v     Print version and exit.

SIGNALS

       iscsid reacts to a set of signals.  You may easily send a signal to iscsid using the following:

	      kill -SIGNAL `cat /var/run/iscsid.pid`

       SIGTERM
	      The daemon and all of it's children will die.

       SIGHUP sent  to the main daemon process will restart all discovery processes and reprobe LUNs on all targets.  iscsid and all of it's chil-
	      dren will die after shutting down all of the kernel's iSCSI sessions.

       SIGCHLD
	      Wait for children.

NOTES

       The iSCSI Driver for Linux provides IP access to a maximum of sixteen remote SCSI targets.  Each target will be probed for up to 256  LUNs,
       until the Linux kernel's limit of SCSI devices has been reached.

       The iSCSI drivers, README files, and example configuration files are available on the Linux-iSCSI homepage at:

       http://linux-iscsi.sourceforge.com/ <http://linux-iscsi.sourceforge.com/>

FILES

       /etc/iscsi.conf
	      target address and LUN configuration

       /var/run/iscsi.pid
	      the process id of the running daemon

       /var/iscsi/bindings
	      persistent bus and target id bindings for iSCSI TargetNames

       /proc/scsi/iscsi
	      information about iSCSI devices

       /dev/iscsi
	      a directory tree containing symlinks to iSCSI device nodes.

SEE ALSO

       iscsi.conf(5)

$Revision: 1.8 $					   $Date: 2002/09/20 19:27:32 $ 						 ISCSID(8)