I'm new to handling the infrastructure for production service deployments. My intuition tells me that if I want to have my service be "up" as much as possible and yet can only afford say 2 dedicated servers (startup time!) that I should make one server a redundant copy of the other. Then setup failover, replication, etc.
However, after reading some case studies and even hearing that Stack Overflow and OK Cupid only have a single database server, perhaps I'm overthinking things?
I kind of hate having to spend say $250/mo. on a leased server that acts as a backup just in case.
This all depends on your service that you provide but come on, Stack Overflow must be important enough that it should require a redundant database.
OK, enough rambling. What am I missing? Help! Thanks.