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1.9. iSCSI Discovery Configuration

The default iSCSI configuration file is /etc/iscsi/iscsid.conf. This file contains iSCSI settings used by iscsid and iscsiadm.
During target discovery, the iscsiadm tool uses the settings in /etc/iscsi/iscsid.conf to create two types of records:
Node records in /var/lib/iscsi/nodes
When logging into a target, iscsiadm uses the settings in this file.
Discovery records in /var/lib/iscsi/discovery_type
When performing discovery to the same destination, iscsiadm uses the settings in this file.
Before using different settings for discovery, delete the current discovery records (i.e. /var/lib/iscsi/discovery_type) first. To do this, use the following command:
iscsiadm -m discovery -t discovery_type -p target_IP:port -o delete[1]
Here, discovery_type can be either sendtargets, isns, or fw. [2]
There are two ways to reconfigure discovery record settings:
  • Edit the /etc/iscsi/iscsid.conf file directly prior to performing a discovery. Discovery settings use the prefix discovery; to view them, run:
    iscsiadm -m discovery -t discovery_type -p target_IP:port
  • Alternatively, iscsiadm can also be used to directly change discovery record settings, as in:
    iscsiadm -m discovery -t discovery_type -p target_IP:port -o update -n setting -v %value
    Refer to man iscsiadm for more information on available settings and valid values for each.
After configuring discovery settings, any subsequent attempts to discover new targets will use the new settings. Refer to Section 1.11, “Scanning iSCSI Interconnects” for details on how to scan for new iSCSI targets.
For more information on configuring iSCSI target discovery, refer to the man pages of iscsiadm and iscsid. The /etc/iscsi/iscsid.conf file also contains examples on proper configuration syntax.

[1] The target_IP and port variables refer to the IP address and port combination of a target/portal, respectively. For more information, refer to Section 1.2.1, “iSCSI API” and Section 1.11, “Scanning iSCSI Interconnects”.
[2] For details on different types of discovery, refer to the DISCOVERY TYPES section of man iscsiadm.