How to manage a backup mail server with ISPConfig 3?

Hello to everybody.
Following the tutorial for a perfect email server with centos and ISPConfig, I've configured a mail server with ISPConfig 3 and roundbube as webmail.
What I need now is to have a backup copy of that server, so that when the main server crash for some reasons, the backup server became main server.
It could be amazing even if, after the crash of the main server, the system can send me an error message.

Any idea?
Thanks
Michele

 

No suggestions?

 

It should be possible to set up such a backup server with the help of rsync and MySQL replication.

 

In another discussion (http://www.how2forge.org/forums/showthread.php?p=202955&posted=1#post202955) till suggest me to go through GlusterFS and a MySQL syncronization... But at the moment I'm still working about that... suggestions are accepted...