The ever so much feared downtime and its effects on search engine rankings have sprung up conversation at the WebmasterWorld supporters forum (paid access only). The thread is named My server is in Houston & Hurricane Rita's Coming, Should I Move it ASAP?
But what about the damage it can have on an online business. Many hosting farms are located in Texas, and what if those hosts go down and are not operational for 12 hours, 1 day, 2 days and so on? Besides for the fact that if your site is down for any number of hours, you are losing potential sales and customers. What about the affect it can have on your search engine rankings?
The longer you are down, the higher the potential for a negative impact on search engine rankings. Personally, I think it is logical to assume being down for 12 hours will not impact your rankings in the engines. But beyond that, I do not know. All the engines say they keep trying, but for how long?
So how should you prepare? (1) Get your sites set up on a backup server, in a different location. (2) Make sure all the files and databases are sync'ed up frequently. (3) Lower the TTL (time to live) to the lowest maximum you can. (4) Test the backup server. (5) Get ready to change your DNS information to point over the domain names to the new server's IP addresses. If the TTL is low enough, you can expect some name servers to update within 30 minutes or less, whereas others can take up to 48 hours.
Paid forum discussion at WebmasterWorld.