Very High reliability e-mail

Hi people,

I have requirements for mission critical e-mail, that would require a minimum of two mail servers in a cluster.

Has anyone done this with Interworx? The way I see doing this is having 2x Barracuda spam firewalls in two locations and pointing DNS to that and then if the server fails we can get it send to a new IP of the server that has stepped in for that client.

However would like something automatic.

Could we rsync every 5 mins or so, the SMTP config and data over to a backup server which could serve as our backup and put that server in as the secondary MX priority?

How is everyone else doing it?

Your answers are much appreciated.

Elaborate on the High Reliability. If it’s to prevent downtime I would use Postini, they offer a phenomal spooling service included as well as spam protection.

Can iworx be used as a standby MX or backup (store-and-forward) mail server?