more than two way replication

[B]

Dirk,

On Wed, Sep 02, 2015 at 08:27:42PM +0100, djk wrote:
> Is there anyway of replicating between more than one other instance
> of Dovecot. I have bidirectional replication working successfully and
> it seems to be reliable. I would like to replicate from one or more
> of these instances to one other. Is this possible?

I've asked the same question a few months ago and was looking at having multiple mail_replicas or using round robin DNS for the mail_replica.

Here's how I "solved" it:

Server A, B, C

A -> B 
on A set mail_replica = B
Mail arrives at A, syncs to B

B -> C
on B set mail_replica = C
Mail arrives at B, syncs to C

C -> A
on C set mail_replica = A
Mail arrives at C, syncs to A

The more you add the higher the delays.
Not the best solution but it works.

Timo please add multiple mail_replicas and maybe priorities for high latency links.

HTH

B.