There are new laws to require large banks to have redundancy in place. IIRC min. 3000 miles between data centers. Also there is a law that no one bank can have more than 10% of the total deposits for the US, I believe it was BoA or City who just hit that limit with their most recent buyout oif a smaller bank.
A lot of the larger banks now resell their services to smaller regional banks so your little hometown mom and pop bank may even have some of their services outsourced to a large bank and therefore your funds may still be available even if the local bank is completely destroyed.