On 18/10/2022 12:17, Michael wrote:
>
> [...]
so, raid is mandatory, which is already the case, but what about backup?
how can i achieve a backup/snapshot of both, the mdbox (nfs share) and
the index files (local raid) and assure they are consistent?
You can use doveadm to backup the mailboxes, which should work correctly
even in a live system.
My backup "strategy" (hopefully it deserves that name) is to weekly run
something like:
for MAILBOX in $USERS; do
doveadm expunge -u "$MAILBOX" mailbox Trash savedbefore 7d
doveadm expunge -u "$MAILBOX" mailbox Spam savedbefore 30d
doveadm purge -u "$MAILBOX"
LOCATION2="mdbox:/srv/snap_mail/$MAILBOX/mdbox"
doveadm -v backup -u "$MAILBOX" -P "$LOCATION2"
done
which makes a replica of the mailbox (including dovecot.list.index, but
e.g. dovecot-uidvalidity is not there, I don't know if this is bad or not).
Once you have this "snapshot" of the mailbox(es), you can rsync them to
wherever you like (so you avoid rsync'ing a changing system).
I've never had to restore from backup (rsync back, and either doveadm
backup back in the other direction), but I'd tend to assume this should
work fine.
BTW I use mdbox_rotate_interval = 0 and mdbox_rotate_size = 64M, so the
mdbox'es have a relatively big size (but not too big), which is nice for
rsync.
Cheers,
Bernardo
