Issue: I am testing controller fail over and fail back on my VTrak E-Class unit connected to a Qlogic 9000 series FC Switch. When I pull one of the two controllers Fail-Over is not seamless i.e. I/O fails and my XSAN volume goes down.

Solution: In order for target Fail-Over and Fail-Back to work properly it is essential that the FC port settings are correct on the QLogic FC switch.

Please see the following Apple knowledge base articles regarding Qlogic FC port settings:

Using QLogic switches with Apple Fibre Channel Cards
Qlogic 9000 series switches: During setup, Initiators won't recognize Targets