25.15. Scanning iSCSI Interconnects For iSCSI, if the targets send an iSCSI async event indicating new storage is added, then the scan is done automatically. However, if the targets do not send an iSCSI async event, you need to manually scan them using the iscsiadm utility. Before doing so, however, you need to first retrieve the proper --targetname and the --portal values. If your device model supports only a single logical unit and portal per target, use iscsiadm to issue a sendtargets command to the host, as in: The output will appear in the following format: Example 25.11. Using iscsiadm to issue a sendtargets Command For example, on a target with a proper_target_name of iqn.1992-08.com.netapp:sn.33615311 and a target_IP:port of 10.15.85.19:3260 , the output may appear as: In this example, the target has two portals, each using target_ip:port s of 10.15.84.19:3260 and 10.15.85.19:3260 . To see which iface configuration will be used for each session, add the -P 1 option. This option will print also session information in tree format, as in: Example 25.12. View iface Configuration For example, with iscsiadm -m discovery -t sendtargets -p 10.15.85.19:3260 -P 1 , the output may appear as: This means that the target iqn.1992-08.com.netapp:sn.33615311 will use iface2 as its iface configuration. With some device models a single target may have multiple logical units and portals. In this case, issue a sendtargets command to the host first to find new portals on the target. Then, rescan the existing sessions using: You can also rescan a specific session by specifying the session's SID value, as in: If your device supports multiple targets, you will need to issue a sendtargets command to the hosts to find new portals for each target. Rescan existing sessions to discover new logical units on existing sessions using the --rescan option. Important The sendtargets command used to retrieve --targetname and --portal values overwrites the contents of the /var/lib/iscsi/nodes database. This database will then be repopulated using the settings in /etc/iscsi/iscsid.conf . However, this will not occur if a session is currently logged in and in use. To safely add new targets/portals or delete old ones, use the -o new or -o delete options, respectively. For example, to add new targets/portals without overwriting /var/lib/iscsi/nodes , use the following command: To delete /var/lib/iscsi/nodes entries that the target did not display during discovery, use: You can also perform both tasks simultaneously, as in: The sendtargets command will yield the following output: Example 25.13. Output of the sendtargets Command For example, given a device with a single target, logical unit, and portal, with equallogic-iscsi1 as your target_name , the output should appear similar to the following: Note that proper_target_name and ip:port,target_portal_group_tag are identical to the values of the same name in Section 25.7.1, "iSCSI API" . At this point, you now have the proper --targetname and --portal values needed to manually scan for iSCSI devices. To do so, run the following command: Example 25.14. Full iscsiadm Command Using our example (where proper_target_name is equallogic-iscsi1 ), the full command would be: [7] For information on how to retrieve a session's SID value, refer to Section 25.7.1, "iSCSI API" . [8] This is a single command split into multiple lines, to accommodate printed and PDF versions of this document. All concatenated lines - preceded by the backslash (\) - should be treated as one command, sans backslashes.

Commands:
iscsiadm -m discovery -t sendtargets -p target_IP:port [5]
target_IP:port , target_portal_group_tag proper_target_name
10.15.84.19:3260,2 iqn.1992-08.com.netapp:sn.33615311 10.15.85.19:3260,3 iqn.1992-08.com.netapp:sn.33615311
Target: proper_target_name Portal: target_IP:port , target_portal_group_tag Iface Name: iface_name
Target: iqn.1992-08.com.netapp:sn.33615311 Portal: 10.15.84.19:3260,2 Iface Name: iface2 Portal: 10.15.85.19:3260,3 Iface Name: iface2
iscsiadm -m session --rescan
iscsiadm -m session -r SID --rescan [7]
iscsiadm -m discovery -t st -p target_IP -o new
iscsiadm -m discovery -t st -p target_IP -o delete
iscsiadm -m discovery -t st -p target_IP -o delete -o new
ip:port,target_portal_group_tag proper_target_name
10.16.41.155:3260,0 iqn.2001-05.com.equallogic:6-8a0900-ac3fe0101-63aff113e344a4a2-dl585-03-1
iscsiadm --mode node --targetname proper_target_name --portal ip:port,target_portal_group_tag \ --login [8]
iscsiadm --mode node --targetname \ iqn.2001-05.com.equallogic:6-8a0900-ac3fe0101-63aff113e344a4a2-dl585-03-1 \ --portal 10.16.41.155:3260,0 --login [8]