Hi Nopan,
Basically MIB files are not used to monitor the Health of physical drives or any other components of the MSA,
MSA its self monitors the Health of the compoents and reports the event in the MSA Event log, MSA do not sent the complete events to the SNMP Server, it converts the event in to SNMP Traps and sent to the SNMP Server,
When the SNMP server receives the Trap, it decodes the Trap using the Respective Array MIB files(MSA2040 or P2000 etc) and displays the event in readable format.
So there is no MIB file required to check the Health of the Hard drive, its a single MIB file which can decode all the SNMP Traps sent by the MSA.
Hope this helps!
Regards,
Venkat.