Now it's time to get serious. For several pages, we have discussed all the components that go into a stable server, and have strongly suggested obtaining multiple spares for each. Well, that applies to the server itself. Not only does this mean having a spare idle server in case of a catastrophic failure, but it means having an online server as well.
Determining how many excess servers we should have isn't quite that simple, but it's fairly close. This is where the project starts to get expensive, but high availability is never cheap; the company itself might depend on it.
