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VMware ESXi w/ iSCSI boot - controller failover behavior

Question asked by jjohnston1127 on Feb 28, 2015
Latest reply on May 14, 2015 by Gary Martin



I have ran into many occurrences over time where ESXi hosts throw up an alarm stating they lost connectivity to the datastore backing the boot filesystem if they were booted using iSCSI.  I have experienced it on any array that supports iSCSI boot and the only fix is to restart the management agent on the hosts. This usually happens during a storage controller failover.  The storage controller failover process usually takes anywhere from 15-30 seconds.


I was doing some research and found a software iSCSI adapter setting named Recovery Timeout that, according to Cormac Hogan, is the number of seconds before an active path is marked dead.  It is currently set to 10 seconds.  I was wondering if I changed the setting to something like 60 seconds if there would be any adverse affects anyone could think of.  My thought is within 60 seconds the controller failover process should have completed and in the rare case that both controllers are dead it wouldn't matter if 60 seconds went by before the hosts started freaking out.