[Dovecot] Dovecot load balancing

[Chris Laif]

On Thu, Jul 31, 2008 at 3:26 PM, Thomas Hummel <hummel at pasteur.fr> wrote:
> On Thu, Jul 31, 2008 at 03:07:28PM +0200, Chris Laif wrote:
>
>> Do you use dovecot's delivery agent (LDA)?
>
> As I stated, no. I need the procmail filtering features.
>

As stated in the other mails, you can use procmail *and* dovecot's
LDA. then, your cache files are updated on *every* operation on a
mailbox (storing and fetching mails)

>> 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.
>
> I see, something like adding a hostName LDAP attribute to all my users in LDAP
> dans putting this in dovecot-ldap.conf :
>

I've no experience with LDAP. If you use a SQL-db the setup is
non-trivial but doable :) For example, you've got 3 servers: If the
user hits the right server, he accesses the local mailbox. If he hits
the "wrong" server, the SQL-db finds out where his mails are stored
and proxies him to the right server.

If you add SQL-replication, you've got an nice setup without a single
point of failure (SPOF). If one server crashes, some (!) mailboxes are
unavailble but you can restore a backup to one of the live servers and
update the mail storage location in the SQL-db accordingly.

I do not like NFS that much (various NFS-problems, SPOF), therefore I
recommend the above solution.

Chris