Backup Guide
First off you should have a backup of your configuration.nix file
where you have the server config (but that is already in a git
repository right?)
Next you need to backup /var/vmail or whatever you have specified for the
option mailserver.storage.path. This is where all the mails reside.
Good options are a cron job with rsync or scp. But really anything
works, as it is simply a folder with plenty of files in it. If your backup
solution does not preserve the owner of the files don’t forget to chown them
to virtualMail:virtualMail if you copy them back (or whatever you specified
as mailserver.storage.owner, and mailserver.storage.group).
To backup spam and ham training data, backup /var/lib/redis-rspamd.
Finally you can (optionally) make a backup of /var/dkim (or whatever you
specified as mailserver.dkim.keyDirectory). If you should lose those
don’t worry, new ones will be created on the fly. But you will need to update
the DKIM TXT records to reflect the new key material.