17.7.1 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:

  1. Install the scsi-target-utils package:

    # yum install scsi-target-utils
  2. 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.

  3. Start the iSCSI target service, tgtd, and configure it to start after the system reboots:

    # service tgtd start
    # chkconfig tgtd on
  4. 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.