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Discovering new LUNs on Red Hat and SUSE with iSCSI and multipathing

When you are running Red Hat Enterprise Linux 5, 6, and 7 series or SUSE Linux Enterprise Server 10, 11, or 12 series with DM-Multipath and the software iSCSI initiator, you can discover new LUNs by rescanning the iSCSI service on the host. Rescanning the service displays all the newly created LUNs that have been mapped to the host.

Before you begin

You must have a copy of the rescan script. The rescan script is available with the sg3_utils package. In addition, the rescan script is available with Red Hat Enterprise Linux 5 Update 4 or later, Red Hat Enterprise Linux 6, 7 series, SUSE Linux Enterprise Server 10 SP2 or later, SUSE Linux Enterprise Server 11, 12 series.

About this task

You cannot view new LUNs until the operating system discovers them. After the LUNs have been discovered, they are automatically added to the DM-Multipath configuration.

Note: You can use the rescan script to discover new LUNs in environments that are using multipathing and those that are not.


  1. To discover a new LUN on a system running DM-Multipath, enter one of the following commands:
    If you want to... Enter the following command...
    Obtain the list of all the current sessions iscsiadm -m session
    Rescan a specific session iscsiadm -m session --sid=N --rescan

    N is the specific session ID.

    Rescan all the sessions iscsiadm -m session --rescan
    Rescan using the SCSI rescan script /usr/bin/
  2. To verify that the new LUNs have been discovered, use the sanlun command or the iscsiadm command.