Iscsi - target and initiator setup debian

iSCSI - target (server) setup

We'll use tgt to handle everything dynamically

iSCSI - initiator (client) setup

Link to page:

http://iscsitargetandinitiator.blogspot.dk/

Show target devices and initiators connected

tgtadm --lld iscsi --op show --mode target

Add devices/disks/partitions to target

tgtadm  --lld iscsi --op new --mode logicalunit --tid 1 --lun 1 -b /dev/sdb

Re-adding LVM based iscsi disks after reboot

Requires a change in how LVM 'attaches' to disks.

So if you've added say /dev/sdb to be a complete iscsi device and on the initiator using it as a LVM, it does not attach itself to the target on reboot.

Edit /etc/lvm/lvm.conf and change:

   # By default we accept every block device:
    #filter = [ "a/.*/" ]
    # Every block device except /dev/sdb, that is.
    filter = [ "r|/dev/sdb|" ]

More info here: http://www.sysarchitects.com/iscsi_target_on_rhel6

On debian I couldn't get this to work; I found a simple init-script from RH bugzillatracker which did the trick:

#!/bin/sh
### BEGIN INIT INFO
# Provides:          tgtd
# Required-Start:    $network $syslog
# Required-Stop:     $network $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      
# Short-Description: Start the iSCSI target server tgt
# Description:       iSCSI target server tgt (http://stgt.sf.net)
### END INIT INFO

set -e

TGTD="/usr/sbin/tgtd"
TGTADMIN="/usr/sbin/tgt-admin"
DEFAULTS="/etc/default/tgt"

# Check for daemon presence
[ -x "$TGTD" ] || exit 0

OPTIONS=""
MODULES=""
# Include tgtd defaults if available
[ -r "$DEFAULTS" ] && . "$DEFAULTS"

# Get lsb functions
. /lib/lsb/init-functions

case "$1" in
  start)
    log_begin_msg "Starting iSCSI target (tgt) services..."
    start-stop-daemon --start --quiet --oknodo --exec "$TGTD" -- $OPTIONS
    [ -x "$TGTADMIN" ] && $TGTADMIN -e
    log_end_msg $?
    ;;
  stop)
    log_begin_msg "Stopping iSCSI target (tgt) services..."
    start-stop-daemon --stop --quiet --oknodo --retry 2 --exec "$TGTD"
    log_end_msg $?
    ;;
  restart)
    $0 stop
    sleep 1
    $0 start
    ;;
  reload|force-reload)
    log_begin_msg "Reloading iSCSI target (tgt) services..."
    start-stop-daemon --stop --signal 1 --exec "$TGTD"
    log_end_msg $?
    ;;
  status)
    status_of_proc "$TGTD" tgtd
    ;;
  *)
    log_success_msg "Usage: /etc/init.d/tgt {start|stop|restart|reload|force-reload|status}"
    exit 1
esac

iSCSI with HA

Attached pdf document which describes DRBD, Pacemaker and iSCSI setup:

File:Ha-iscsi.pdf

iSCSI Linux links

Good tgt-based setup Howto add UDEV rules for exposed disks Simple howto with debian initiator and target initiator non-tgt setup Simple setup open open-iscsi