On my McData switches MIB is FA Mib 3.1. I don’t see any config options for SNMP other than target and port. You shoulsd be able to go in and pull all 3 log sets:
Link incident, open-trunking reroute, and event logs. You can also gather all logs at once.
You probably aren’t overloading the switch, but that should be easy enough to test. Start the backup process and see if you start loosing packets between you and the management port of the switch. Is just one switch having the problem, or is the other switch (I’m assuming you have two) having the problem as well?
I know with my Cisco FC switches I’m able to use MRTG to track the bandwidth that each port is using just like I can with an Ethernet switch. I would assume that the same can be done with a McData switch.