Symmetrical devices allow for automatic failback to a possible optimal path. If a failover occurs on the initial path, the standby path becomes the new online path. Usually the standby path is a suboptimal path. When auto-failback is enabled, the initial path comes back online, failover to the initial path automatically occurs.
Run the mpathadm list mpath-support command.
# mpathadm list mpath-support mpath-support: libmpscsi_vhci.so |
Select an mpath support name from the output list.
Run the mpathadm modify mpath-support -a [on | off] mpath-support-name command.
# mpathadm modify mpath-support -a off libmpscsi_vhci.so |
Run the mpathadm show mpath-support mpath-support-name command to check the change.
# mpathadm show mpath-support libmpscsi_vhci.so mpath-support: libmpscsi_vhci.so Vendor: Sun Microsystems Driver Name: scsi_vhci Default Load Balance: round-robin Supported Load Balance Types: round-robin logical-block Allows To Activate Target Port Group Access: yes Allows path Override: no Supported Auto Failback Config: yes Auto Failback: on Failback Polling Rate (current/max): 0/0 Supported Auto Probing config: no Auto Probing: NA probing Polling Rate (current/max): NA/NA Supported Devices: Vendor: SUN Product: T300 Revision: Supported Load Balance Types: round-robin Vendor: SUN Product: T4 Revision: Supported Load Balance Types: round-robin |
The auto-failback display initiated by the mpathadm modify command setting is effective while the system is running. However, to keep the changed setting persistent, you must update the /kernel/drv/scsi_vhci.conf file. Refer to Configuring Automatic Failback.