Setting up replication - First steps...

[SH Development]

Just had my first (non-Dovecot) server failure due to dried out caps on the motherboard.  Got me to thinking about my single-point-of-failure mail server.  Currently running Dovecot and Postfix with no issues, but want to start taking steps just to be safe.

I currently run a filesystem backup every 24 hours to a tar file over NFS to another server in our rack.  I am backing up:

/home/vmail
/etc/dovecot
/etc/postfix

Unfortunately, the vmail directory has grown to 27GB and takes around 7 hours now to backup as described above.  Which leads me to start thinking about how quickly I could restore the server from a backup if need be, and that time is at least 7 hours just to copy and untar the files onto another hard drive. I’m sure I could hook up a HD up directly to the backup server, then I could considerably reduce the time, but I’m making the assumption that I won’t always have quick physical access to the location.

So I believe my first step is to set up another server, on another IP, different hostname, with Dovecot and Postfix, and simply use the files from the /etc directories of the existing server to configure it (changing the IP and hostname of course).

Am I on the right track so far?

Next steps involve setting up replication with dsync?

If I have successfully setup replication between the two servers, does this mean users can then actually log into either server and have their “stuff” intact?  So I could set up DNS failover in case the primary server fails?  Would this make the setup acceptable for secondary MX as everything should sync to the primary server when it comes back online?

Sorry for thinking out loud, but I want to make sure I’m understanding the bigger picture here.

Jeff