[Dovecot] Dovecot load balancing

Gabriel Millerd
Thu, 31 Jul 2008 14:21:16 -0000

On Thu, Jul 31, 2008 at 7:15 AM, Thomas Hummel <hummel at pasteur.fr>
wrote:
>
> I don't think that DNS round robin would do the trick because some UA
(for
> instance Thunderbird) often open up to 5 connexions for the same user,
unless
> maybe such UA makes a single 'gethostbyname()', thus connecting 5
times to the
> same physical server ?
>

I am not seeing the issue, your seeing issues with the UA spreading
the connects across multiple servers? If so are the message-ids
different for imap://hummel@ on one machine versus another? The same
filer for a backend right?

I assume that authentication, and more, is caching on Dovecot. So the
actual LDAP hits are solitary for the whole lifetime of the UA session
most likely.

Dovecot as a LDA is ideal, as stated above, it will do the initial
indexing upon delivery of messages and dovecot-imap will fixup as
needed.

Perhaps the UUIDS for pop and imap can be looked at for speed ups.

Having a lot of processes, and in what state are they in? If the bulk
of them are running because of searches (like outlook crazy queries or
virus checkers than scan 1gb of mail etc) Thats a problem that is a
little outside load balancing it seems.

I would see the pre-delivery being more of a issue than dovecot
performance wise especially with the LDA, hefty caching, and good
maildir file naming.

--
Gabriel Millerd