25.6. iSCSI

This section describes the iSCSI API and the iscsiadm utility. Before using the iscsiadm utility, install the iscsi-initiator-utils package first by running yum install iscsi-initiator-utils.
In Red Hat Enterprise Linux 7, the iSCSI service is lazily started by default. If root is not on an iSCSI device or there are no nodes marked with node.startup = automatic then the iSCSI service will not start until an iscsiadm command is run that requires iscsid or the iscsi kernel modules to be started. For example, running the discovery command iscsiadm -m discovery -t st -p ip:port will cause iscsiadmin to start the iSCSI service.
To force the iscsid daemon to run and iSCSI kernel modules to load, run systemctl start iscsid.service.

25.6.1. iSCSI API

To get information about running sessions, run: 
# iscsiadm -m session -P 3
This command displays the session/device state, session ID (sid), some negotiated parameters, and the SCSI devices accessible through the session.
For shorter output (for example, to display only the sid-to-node mapping), run: 
# iscsiadm -m session -P 0
or 
# iscsiadm -m session
These commands print the list of running sessions with the format: 
driver [sid] target_ip:port,target_portal_group_tag proper_target_name

Example 25.3. Output of the iscsisadm -m session Command

For example: 
# iscsiadm -m session

tcp [2] 10.15.84.19:3260,2 iqn.1992-08.com.netapp:sn.33615311
tcp [3] 10.15.85.19:3260,3 iqn.1992-08.com.netapp:sn.33615311
For more information about the iSCSI API, refer to /usr/share/doc/iscsi-initiator-utils-version/README.