Hello everyone,
we are working on migrating from dovecot 2.0.9 (maildir) to 2.2.36 (mdbox). The new cluster has two backend mail servers which replicate through doveadm replicator. To move the data initially we use doveadm backup (imapc).
Our migration command doveadm -o mail_fsync=never backup -R -u $user imapc:
To test the replication of new and purge of old mails with live data changes we ran imapc on a daily basis but encountered the problem that some mailboxes multiplied in size. We then made sure that imapc and replication don't run at the same time but after the first incremental imapc process, we still had the same problems.
The doveadm-backup man-page states that it's possible to run it multiple times during migration. But is it also possible to have the replicator running in between? From our understanding the doveadm backup should just work as an imap connection between the servers, synchronizing all changes made on the source to the destination. Or does the conversion from maildir to mdbox format in our case produce the problems?
If you're not supposed to run the replicator before having fully migrated, how can we shorten the downtime? rsync? And how can we be sure that similar problems don't occur after the migration if we can't test all mechanisms together with live data?
thanks
Thomas Winterstein