[Dovecot] Performance-Tuning

[Timo Sirainen]

On 8.11.2011, at 16.34, Peer Heinlein wrote:

>> I can of course use dsync to mirror Maildir: to mdbox:, but how can I
>> make dovecot look at Maildir FIRST and (if that fails) at mdbox? (or
>> vice versa).
> 
> I wonder about that problem too. Even the last-last-last-quick sync would be 
> so much IO, that I can't handle it in realtime in the morning at 9 a.m.
> 
> Looks like a nightly downtime for the last incremental run.
> 
> It would be MUCH easier if Dovecot could read maildir: or mdbox: from LDAP 
> attributes.

Easy!

> In this case the whole migration process could be split up into 
> groups. Unfortunately we have shared folders and I don't know a way to read 
> the *remote* mailbox-format from LDAP... So having users with maildir and 
> mdbox mixed up will break their shared folders...

Not so easy.. Only the home directory can be currently looked up from userdb for shared folders.

There is also automatic detection of Maildir and mbox when mail_location isn't set, but no such code for mdbox. It could be added without much trouble though. But for shared folders, assuming you'd want per-user \seen flags, it would also need something like:

mail_location = auto::INDEX=~/shared-indexes

This "auto" doesn't exist yet either. And then there's the biggest problem: You can't have per-user \seen flags with mdbox, because you can't change the index file path without breaking mdbox.