We have a pair of PIX 535 6.3(5) one with UR and other with FO license. We are going to upgrade the cards in the first 3 slots to GiGE and want to minimise any downtime. If we power off the PIX with the UR license and disconnect all cables including the failover cable in order to unrack it and perform the upgrade will the PIX with the FO license continue to work? Looking on CCO it states that:-
"The PIX Firewall failover unit is intended to be used solely for failover and not in standalone mode.
If a failover unit is used in standalone mode, the unit will reboot at least once every 24 hours until
the unit is returned to failover duty"
So is there the possibility that while upgrading the hardware (say 60 mins max) on the UR PIX the FO PIX will reboot - and then hang on boot up as it is not connected to the UR PIX causing a loss of service?
(After upgrading of the UR PIX the same ipgrade will then be performed on the FO PIX!)