

Planning for catastrophe - stymiee
http://webmasters.stackexchange.com/q/16746/1253

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spydum
He/She should be asking: What can I afford, and what kind of RTO/RPO's do I
have? Does the entire system need to be back up? Can you survive with a
stream-lined version of your infrastructure? Do you think you can restore your
systems on the failover site faster than your provider can restore service?
This is a big one -- failing over may cause your site to be out longer if the
provider restores service mid-way through -- and by then, your DNS changes may
have already begun to propagate.

If your business really requires to be up all the time, perhaps you should be
looking at multiple online sites (active/active), with failover just at the
data layer. That means duplicating your environment (down to hosting your own
DNS servers at each site), and fighting all of the typical replication issues.

