How to backup maildir

[Robert Moskowitz]

I have been thinking, and reading, on how to back up my mailserver. I 
have not found any approach that seems ready to use.


I have run years without any backup, but would really like to have 
something in place.  I figure I can attach a USB drive and backup to 
that, then from there rsync to something elsewhere.  Further if that USB 
drive is a full mailserver image, I actually have a 'hot backup' where I 
only have to put the backup drive into a system and boot up at the last 
backup.

But this means properly copying all of /home/vmail and probably 
/home/sieve plus the /var/lib/mysql

Are there good tools that nicely does this?  Or do I choose a time late 
at night (only I am sometimes in non-US timezones) to shut down all 
services and just use rsync?

And stopping services itself is thought provoking.  What if Dovecot, 
amavis, mysql, or whatelse is in the middle of writing out a mail file 
what happens to that file and restart.

Just scary stuff and, in part, why I have never tackled this in the past.

thanks for all feedback