DMP failover takes significant time when the path is disabled from the switch or array side in a SAN environment. This issue is not seen if the path is disabled from the host side. The dynamic tracking and fast fail features of AIX prevent the long failover time.
To configure the AIX fast fail feature for use with VxVM and DMP
Enter the following commands for each Fibre Channel adapter or controller:
# chdev -l fscsiN -a fc_err_recov=fast_fail -P # chdev -l fscsiN -a dyntrk=yes -P
where N is the number of the controller (0, 1, 2 and so on).
Use the lsattr command to verify that the dyntrk and fast_fail attributes are set to True on each adapter, as shown in this example:
# lsattr -El fscsi0 attach switch How this adapter is CONNECTED False dyntrk yes Dynamic Tracking of FC Devices True fc_err_recov fast_fail FC Fabric Event Error Recovery Policy True scsi_id 0x10d00 Adapter SCSI ID False sw_fc_class 3 FC Class for Fabric controllers. True