[Dovecot] Disk busy issues

[Timo Sirainen]

On Dec 4, 2009, at 8:58 AM, Michael Durket wrote:

> I'm wondering if the problem here is that all the mailboxes for these users are in mbox
> format and that format just poses too much of a burden on Dovecot.

If you haven't yet set mbox_very_dirty_syncs=yes, doing it should help.

> I personally as an
> experiment have been using Maildir format and that seems to work fine. Would people
> on this forum (who probably deal with larger numbers of users and mailboxes than my
> system does) recommend that I switch the mailboxes over to Maildir format to alleviate
> the disk busy problems?

Depends on usage patterns, but I guess it could help. With v1.2 you could also set maildir_very_dirty_syncs=yes to improve its performance.

> Are there any issues to watch out for when converting mailboxes
> from mbox to Maildir format?

Make sure IMAP UIDVALIDITY + UIDs are preserved. Apparently the mb2md.py script in http://wiki.dovecot.org/Migration/MailFormat can do it. And do you have POP3 users? Their UIDLs should also be preserved.