Our companies' Disaster Recovery Plan calls for instant return of service after network configuration has been updated. For us the ideal backup situation would be a mirror installation of our existing Zimbra, where the existing zimbra sends a copy of every message sent and recieved by the users through the existing server off to the backup server. That way in the event of a massive failure, our users get rerouted to the hot backup host and have access to all of their email. This would also prevent deletion of messages that would later need to be retrieved for regulatory searches. This would also allow easy restore of a mailbox, I think.
This is planned...
This is planned for a future release. Please check out bug 11423.
Perhaps some other folks have stopgap solutions until that is complete?
I think we could handle a slow restore, since this is in the case of a true disaster and the loss of our datacenter, something that just forwards a copy of the sent and received mail as it happens off to the hot backup would be more than sufficient. I suspect it would take us a while to replace our datacenter if it were lost. Since the plan for the hot backup is to run in a VM, the hot backup would most likely become the new master once deployed on stronger hardware.
It seems like scriptable access to the incoming and outgoing mail queues are the solution here..
Maybe this can be done with postfix? I'm not an expert there
Archiving feature in 4.5
I believe that there's an archiving feature in the 4.5 Network release that may do what you want. You may want to contact email@example.com for more info.