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create shared iscsi LUNs from local disk on Linux

January 19th, 2016

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!


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