[lamontcg]

That is about the amazon.com architecture as late as 2006 (only slightly higher scale of three entire datacenters scattered around virginia and I think dual 40G links between datacenters, but other than that exactly the same principles).

Lot of people think that DC failover needs to be east coast / west coast but you can achieve most of your DC redundancy goals separated by 100 miles or less and have a lot lower latency, higher bandwidth and lower costs. Might want to think about different geographic flood plains and different power companies / grids.

Could still nerd fight about EMPs from nuclear war and a sufficiently massive hurricane or an earthquake out here on the west coast, but at some point you need to accept some risks.