ISCSI Initiator

Summary
How to access an iSCSI Target with an initiator.
Series
iSCSI Target
iSCSI Initiator
Related
iSCSI Boot

With Wikipedia:iSCSI you can access storage over an IP-based network.

The exported storage entity is the target and the importing entity is the initiator.

The preferred initiator is Open-iSCSI as of 2011. An older initiator, Linux-iSCSI, was merged with Open-iSCSI. Linux-iSCSI should not be confused with linux-iscsi.org, the website for the LIO target.

Setup With Open-iSCSI

Even open-iscsi is not in the official repositories, so you need to build it from AUR.

Using the Daemon

You only have to include the IP of the target as SERVER in /etc/conf.d/open-iscsi at the client.

At the server (target) you might need to include the client iqn from /etc/iscsi/initiatorname.iscsi in the acl configuration.

After both steps are finished you should be able to start the initiator with

# systemctl enable open-iscsi.service
# systemctl start open-iscsi.service

You can see the current sessions with

# systemctl status open-iscsi.service

Using the Tools

iscsid has to be running.

Target discovery

# iscsiadm -m discovery -t sendtargets -p <portalip>

Delete obsolete targets

# iscsiadm -m discovery -p <portalip> -o delete

Login to available targets

# iscsiadm -m node -L all

or login to specific target

# iscsiadm -m node --targetname=<targetname> --login

logout:

# iscsiadm -m node -U all

Info

For running session

# iscsiadm -m session -P 3

The last line of the above command will show the name of the attached dev e.g

Attached scsi disk sdd State: running

For the known nodes

# iscsiadm -m node

Online resize of volumes

If the iscsi blockdevice contains a partitiontable, you will not be able to do an online resize. In this case you have to unmount the filesystem and alter the size of the affected partition.

1. Rescan active nodes in current session

   # iscsiadm -m node -R

2. If you use multipath, you also have to rescan multipath volume information.

   # multipathd -k"resize map sdx"

3. Finally resize the filesystem.

   # resize2fs /dev/sdx

Tips

You can also check where the attached iSCSI devices are located in the /dev tree with ls -lh /dev/disk/by-path/* .

See also

• iSCSI Boot Booting Arch Linux with / on an iSCSI target.