[Dovecot] Dovecot load balancing

[Chris Laif]

On Thu, Jul 31, 2008 at 2:15 PM, Thomas Hummel <hummel at pasteur.fr> wrote:
> Every friday a message (no attachement, decent size) is sent to all users : in
> such circumstances (but only sometimes, not every time : let's say half the
> time such a message is sent), the load goes so high that I have to stop dovecot
> to let procmail deliver the message or even reboot the machine.
>

Do you use dovecot's delivery agent (LDA)? Dovecot's LDA updates
dovecot's cache file correctly. If you use a different LDA, dovecot
has to re-read directory contents every time (and update the cache
file).

> I know multi-master replication is on the roadmap. I know some dovecot sites
> use in the meantime several dovecot servers. I'd like to know how those sites
> do the load balancing, the main problem beeing to be able to direct each user
> to the same dovecot server each time as stated in the Wiki
> (http://wiki.dovecot.org/NFS).
>

If you use multiple servers you can use dovecot's proxy-feature to
redirect the user to the correct server. You just need a database to
tell dovecot (and the MTA) on how to find the correct location for
that specific user.

Chris