I have an iSCSI LUN that's accesbile via an ifgrp on a node. When I upgrade the node in the HA pair, doesn't the interface fail over to other node therefore there is no downtime? In other words, even though I don't have MPIO set up to access both nodes, the iSCSI connetivity should not go down during the failover and giveback?
how long will it takes on your's?, hard to know. and also depends on the type of failover. but i guess just reduce this regkey to be less than half the timeout your app will tolerate, that's will allow it to try at least twice.