Dovecot infrastructure

[Lorens Kockum]

On Mon, Aug 07, 2017 at 09:14:16AM +0200, Simone Marx :: Edinet Srl wrote:
> Hi,
> I would need some suggestion for a dovecot based mail infrastructure.
> Actually, only one server (with dovecot sendmail amavis spamassassin clamav
> etc etc) is no longer enouth, so I thought I would put on a more complex
> infrastructure on different servers.

Sounds good.

> But I do not know a few things.
> I was thinking about partitioning users on 3-4 servers with dovecot (imap /
> pop3) and dovecot-lda (no networked filesystem between them) and then
> configuring 1-2 servers with dovecot director and 1-2 servers for SMTP with
> postfix.

Sounds a bit less good. If you only have one server now, then
partitioning out by function will probably be *much* easier.
Everything except dovecot is very easy to spread out across
servers, so to take the easy route I would probably keep dovecot
where it is, and spread out the other functions on new servers.
You can have one or two sendmail servers, two or more AV servers,
and add to those as needed. I'll bet that your "not enough"
problems are more related to the AV functions than to dovecot.

The disadvantage of that is that it keeps the dovecot server as a
SPOF. Are you running virtualized infrastructure? If you are,
cool. If you're not, and you won't, then you may want to have
dovecot on more servers, but then you do it for the redundancy,
not for performance! Make sure you get the rest of the redundancy
right. For example, partitioning users across two servers will
not give you redundancy, so doing that will not help you unless
one dovecot server is not enough to handle the load, and since
doing it is a lot of tricky work, I'd certainly postpone doing
it until needed.

Last time I did this I set up storage on a SAN and had one box
running dovecot and one box as a hot spare for any function in
the cluster.

HTH

P.S. BTW... Sendmail?