You can failover a logical unit (LU) in a device, which belongs to one of the following two categories:
Asymmetric devices with a proprietary failover mechanism recognized and supported by multipathing support.
Devices conforming to the T10 standard Target Port Group Support (TPGS) and providing explicit mode ALUA.
# mpathadm show lu /dev/rdsk/c0t600144F0DDA8BB1A000057208C880001d0s2 Logical Unit: /dev/rdsk/c0t600144F0DDA8BB1A000057208C880001d0s2 mpath-support: libmpscsi_vhci.so Vendor: SUN Product: ZFS Storage 7420 Revision: 1.0 Name Type: unknown type Name: 600144f0dda8bb1a000057208c880001 Asymmetric: yes Current Load Balance: shortest-path Logical Unit Group ID: NA Auto Failback: on Auto Probing: NA Paths: Initiator Port Name: iqn.1986-03.com.sun:01:21866c42ab36.5710b544,4000002a00ff Target Port Name: 4000002a0000,iqn.1986-03.com.sun:02:56bf24c4-e3e3-4ff0-e7b0-a6e6880e461d Override Path: NA Path State: OK Disabled: no Target Port Groups: ID: 0 Explicit Failover: no Access State: active optimized Target Ports: Name: 4000002a0000,iqn.1986-03.com.sun:02:56bf24c4-e3e3-4ff0-e7b0-a6e6880e461d Relative ID: 3
You can check the current access state of the Target Port Groups in the output. To ensure that the storage device supports explicit failover, you must verify that the value of Explicit Failover in the output is yes.
# mpathadm failover lu /dev/rdsk/c0t600144F0DDA8BB1A000057208C880001d0s2
If this operation is successful, the access state of the Target Port Groups of the device changes as a result of the logical unit failover.
# mpathadm show lu /dev/rdsk/c0t600144F0DDA8BB1A000057208C880001d0s2 Logical Unit: /dev/rdsk/c0t600144F0DDA8BB1A000057208C880001d0s2 mpath-support: libmpscsi_vhci.so Vendor: SUN Product: ZFS Storage 7420 Revision: 1.0 Name Type: unknown type Name: 600144f0dda8bb1a000057208c880001 Asymmetric: yes Current Load Balance: shortest-path Logical Unit Group ID: NA Auto Failback: on Auto Probing: NA Paths: Initiator Port Name: iqn.1986-03.com.sun:01:21866c42ab36.5710b544,4000002a00ff Target Port Name: 4000002a0000,iqn.1986-03.com.sun:02:56bf24c4-e3e3-4ff0-e7b0-a6e6880e461d Override Path: NA Path State: OK Disabled: no Target Port Groups: ID: 0 Explicit Failover: yes Access State: active optimized Target Ports: Name: 4000002a0000,iqn.1986-03.com.sun:02:56bf24c4-e3e3-4ff0-e7b0-a6e6880e461d Relative ID: 3