What your looking for is a replication server.

The replication server can be turned into a production server or a write only server (replication).

If for any reason the first server goes down then you can turn the replication server to production.

All the replication server will do is copy each and every change you make on the other server to the new one. But its not a easy task as it needs custom scripts.

You can also run a cluster server in which each server connects to each and it will work like a replicated server. But that is something i cannot explain as the documentation is needed since detail is better then just a summary.