In all likelyhood something went wrong hardware-wise. The FCAL map is (re)built every time a disk gets removed or inserted. The fact that you are getting a failure on one adapter, and that you experienced a multi-disk failure points to a hardware problem with a shelf or shelf module. So basically you suffered from a major outage of some kind.
Perhaps a power-cycle might get the shelf back to life, could even be firmware related if you still have an older firmware on one of your shelves. I would advise you to contact support or get someone more experienced to look at your system. You definitely cannot be running cluster mode on a FAS270 on 7.3.2. You probably mean you have an HA pair 🙂