How can you prevent a fire from ever happening again? Disasters happen, its how they handle it thats important.
You can't, however someone as big as Auth.net shouldn't be dependent one 1 datacenter. I find it hard to believe they don't have a distributed network of datacenters.
From what i've heard the fire wasnt even IN their center,it was in the same building and triggered sprinklers in their center.
Wow, if that's true, that is a disaster. Sprinklers near/in a data center :(.
We use PayPal's Payflow Pro (I think it's like $30/month) as our backup. If a transaction fails due to a network error, the payment just gets routed to PayPal. While I wouldn't wish PayPal's payment processing on anyone as their sole provider, I must say, they have been pretty solid as a backup.
Best thing to do though, is just store the payment info temporarily and run the transactions manually once Auth.net is back up.