18.7.1 Configuring an iSCSI Target

The software described in this documentation is either in Extended Support or Sustaining Support. See https://www.oracle.com/us/support/library/enterprise-linux-support-policies-069172.pdf for more information.
Oracle recommends that you upgrade the software described by this documentation as soon as possible.

18.7.1 Configuring an iSCSI Target

An iSCSI target is typically a dedicated, network-connected storage device but it can also be a general-purpose computer. The procedure in this section demonstrates how to set up a simple iSCSI target.

To configure an Oracle Linux system as an iSCSI target:

Install the scsi-target-utils package:
```
# yum install scsi-target-utils
```
Edit /etc/tgt/targets.conf and create entries for the iSCSI target and the storage devices (LUNs) that it will make available, for example:
```
<target iqn.2012-01.com.mydom.host01:target1>
    direct-store /dev/sdb # LUN 1
    direct-store /dev/sdc # LUN 2
</target>
```
The /etc/tgt/targets.conf file contains several sample configurations that you can use as templates.
In the example, the target is uniquely identified by its iSCSI Qualified Name (IQN), which takes the format:
```
iqn.YYYY-MM.reverse_FQDN[:target_name]
```
where:
YYYY-MM
Specifies the year and month that the naming authority took ownership of the domain.
reverse_FQDN
Specifies the reverse fully qualified domain name of the naming authority.
target_name
Specifies an optional target name, which identifies the target at a site.
Start the iSCSI target service, tgtd, and configure it to start after the system reboots:
```
# service tgtd start
# chkconfig tgtd on
```

Use the tgtadm command to verify that the iSCSI target is available:

# tgtadm -o show -m target
Target 1: iqn.2012-01.com.mydom.host01:target1
    System information:
        Driver: iscsi
        State: ready
    I_T nexus information:
    LUN information:
        LUN: 0
            Type: controller
            SCSI ID: deadbeaf1:0
            SCSI SN: beaf10
            Size: 0 MB
            Online: Yes
            Removable media: No
            Backing store: No backing store
        LUN: 1
            Type: disk
            SCSI ID: deadbeaf1:1
            SCSI SN: beaf11
            Size: 10737 MB
            Online: Yes
            Removable media: No
            Backing store: No
...

You can use the tgtadm utility to monitor and configure iSCSI targets. In addition, the tgt-admin script provides a simplifed interface to the tgtadm commands that create, delete, and show target information. The tgt-setup-lun script allows you to create targets, add devices to targets, and define which iSCSI initiators are allowed to connect to a target.

For more information, see the targets.conf(5), tgt-admin(8), tgt-setup-lun(8), and tgtadm(8) manual pages.