System Administration Guide: Devices and File Systems

ProcedureHow to Enable Multiple iSCSI Sessions for a Target

This procedure can be used to create multiple iSCSI sessions that connect to a single target. This scenario is useful with iSCSI target devices that support login redirection or have multiple target portals in the same target portal group. Use iSCSI multiple sessions per target with Solaris SCSI Multipathing (MPxIO). You can also achieve higher bandwidth if you utilize multiple NICs on the host side to connect to multiple portals on the same target.

The MS/T feature creates two or more sessions on the target by varying the initiator's session ID (ISID). Enabling this feature creates two SCSI layer paths on the network so that multiple targets are exposed through the iSCSI layer to the Solaris I/O layer. The MPxIO driver handles the reservations across these paths.

For more information about how iSCSI interacts with MPxIO paths, see Setting Up Solaris iSCSI Multipathed Devices.

Review the following items before configuring multiple sessions for an iSCSI target:

  1. Become superuser.

  2. List the current parameters for the iSCSI initiator and target.

    1. List the current parameters for the iSCSI initiator. For example:


      initiator# iscsiadm list initiator-node
      Initiator node name: iqn.1986-03.com.sun:01:0003ba4d233b.425c293c
      Initiator node alias: zzr1200
              .
              .
              .
              Configured Sessions: 1
    2. List the current parameters of the iSCSI target device. For example:


      initiator# iscsiadm list target-param -v iqn.1992-08.com.abcstorage:sn.84186266
      Target: iqn.1992-08.com.abcstorage:sn.84186266
              Alias: -
              .
              .
              .
              Configured Sessions: 1

      The configured sessions value is the number of configured iSCSI sessions that will be created for each target name in a target portal group.

  3. Select one of the following to modify the number of configured sessions either at the initiator node to apply to all targets or at a target level to apply to a specific target.

    The number of sessions for a target must be between 1 and 4.

    • Apply the parameter to the iSCSI initiator node.

      For example:


      initiator# iscsiadm modify initiator-node -c 2
      
    • Apply the parameter to the iSCSI target.

      For example:


      initiator# iscsiadm modify target-param -c 2  iqn.1992-08.com.abcstorage:sn.84186266
      
    • Bind configured sessions to one or more local IP addresses.

      Configured sessions can also be bound to a specific local IP address. Using this method, one or more local IP addresses are supplied in a comma-separated list. Each IP address represents an iSCSI session. This method can also be done at the initiator-node or target-param level. For example:


      initiator# iscsiadm modify initiator-node -c 10.0.0.1,10.0.0.2
      

      Note –

      If the specified IP address is not routable, the address is ignored and the default Solaris route and IP address is used for this session.


  4. Verify that the parameter was modified.

    1. Display the updated information for the initiator node. For example:


      initiator# iscsiadm list initiator-node
      Initiator node name: iqn.1986-03.com.sun:01:0003ba4d233b.425c293c
      Initiator node alias: zzr1200
              .
              .
              .
              Configured Sessions: 2
    2. Display the updated information for the target node. For example:


      initiator# iscsiadm list target-param -v iqn.1992-08.com.abcstorage:sn.84186266
      Target: iqn.1992-08.com.abcstorage:sn.84186266
              Alias: -
              .
              .
              .
              Configured Sessions: 2
  5. List the multiple paths by using the mpathadm list lu command to confirm that the OS device name matches the iscsiadm list output, and that the path count is 2 or more.