create shared iscsi LUNs from local disk on Linux

We can use iscsitarget to share local disks as iscsi LUNs for clients. Below are brief steps.

First, install some packages:

yum install kernel-devel iscsi-initiator-utils -y #'kernel-uek-devel' if you are using oracle linux with UEK
cd iscsitarget-1.4.20.2 #download the package from here
make
make install

And below are some useful tips about iscsitarget:

The iSCSI target consists of a kernel module (/lib/modules/`uname -r`/extra/iscsi/iscsi_trgt.ko)

The kernel modules will be installed in the module directory of the kernel

The daemon(/usr/sbin/ietd) and the control tool(/usr/sbin/ietadm)

/etc/init.d/iscsi-target status

/etc/iet/{ietd.conf, initiators.allow, targets.allow}

Later, we can modify IET(iSCSI Enterprise Target) config file:

vi /etc/iet/ietd.conf

    Target iqn.2001-04.org.doxer:server1-shared-local-disks
        Lun 0 Path=/dev/sdb1,Type=fileio,ScsiId=0,ScsiSN=doxerorg
        Lun 1 Path=/dev/sdb2,Type=fileio,ScsiId=1,ScsiSN=doxerorg
        Lun 2 Path=/dev/sdb3,Type=fileio,ScsiId=2,ScsiSN=doxerorg
        Lun 3 Path=/dev/sdb4,Type=fileio,ScsiId=3,ScsiSN=doxerorg
        Lun 4 Path=/dev/sdb5,Type=fileio,ScsiId=4,ScsiSN=doxerorg
        Lun 5 Path=/dev/sdb6,Type=fileio,ScsiId=5,ScsiSN=doxerorg
        Lun 6 Path=/dev/sdb7,Type=fileio,ScsiId=6,ScsiSN=doxerorg
        Lun 7 Path=/dev/sdb8,Type=fileio,ScsiId=7,ScsiSN=doxerorg

chkconfig iscsi-target on
/etc/init.d/iscsi-target start

Assume the server sharing local disks for iscsi LUN is with IP 192.168.10.212, and we can do below on client hosts to scan for iscsi LUNs:

[root@client01 ~]# iscsiadm -m discovery -t st -p 192.168.10.212
Starting iscsid:                                           [  OK  ]
192.168.10.212:3260,1 iqn.2001-04.org.doxer:server1-shared-local-disks

[root@client01 ~]# iscsiadm -m node -T iqn.2001-04.org.doxer:server1-shared-local-disks -p 192.168.10.212 -l
Logging in to [iface: default, target: iqn.2001-04.org.doxer:server1-shared-local-disks, portal: 192.168.10.212,3260] (multiple)
Login to [iface: default, target: iqn.2001-04.org.doxer:server1-shared-local-disks, portal: 192.168.10.212,3260] successful.

[root@client01 ~]# iscsiadm -m session --rescan #or iscsiadm -m session -r SID --rescan
Rescanning session [sid: 1, target: iqn.2001-04.org.doxer:server1-shared-local-disks, portal: 192.168.10.212,3260]

[root@client01 ~]# iscsiadm -m session -P 3

You can also scan for LUNs on the server with local disk shared, but you should make sure iscsi-target service boot up between network & iscsi:

mv /etc/rc3.d/S39iscsi-target /etc/rc3.d/S12iscsi-target

PS:

  1. iSCSI target port default to 3260. You can check iscsi connection info in /var/lib/iscsi/send_targets/ - <iscsi portal ip, port>, and /var/lib/iscsi/nodes/ - <target iqn>/<iscsi portal ip, port>.
  2. If there are multiple targets to log on, we can use "iscsiadm -m node --loginall=all".  "iscsiadm -m node -T iqn.2001-04.org.doxer:server1-shared-local-disks -p 192.168.10.212 -u" to log out.
  3. More info is here (includes windows iscsi operation), and here is about create iSCSI on Oracle ZFS appliance.

 

Good Luck & Best Wishes