Is there a way to maintain an exact-replication of my main mail server? For instance a 2nd server that mirrors production so when/if production fails I can redirect traffic to this 2nd server.

I do not expect the cut-over to be quite as simple as I worded it above. Maybe I have to go through DNS and edit entries to point MX to this new server, etc. However, my main question is around a way to duplicate Zimbra data and email on a 2nd server.