How to backup maildir

[Richard Hector]

On 10/02/19 4:50 PM, Robert Moskowitz via dovecot wrote:
> 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.

I use dirvish, which is based on rsync, and which only syncs changed
files but uses hardlinks to keep storage and bandwidth down - it leaves
me with a full copy of the tree for each date, with links between. I run
it on a machine at home.

I don't ususally worry about stopping services; maildir should be all
right. For databases, I use the backup tools provided to back up the
running database, then use dirvish on the backups (and skip the database
files themselves).

I do do it at night, to save load on the server (it's an LXC container
on a VPS).

I believe rdiffbackup does something similar to dirvish.

Richard