Hi,
Dovecot version: 2.2.27
I'm a little unsure if I have set up my replication correctly, and also
how to set up replication on three servers, if this is possible.
My replication works, with exactly the same configuration on both
servers, except that the mail_replica contains the other server name in
each case, of course. This seems to work fine.
As I understand it, both need to be set up as a client and a server,
since I have mail arriving on both. Is this a correct and supported
configuration?
I believe then I should be able to get three-way replication working, by
pointing the three servers at each other in a circle. I am hoping this
will cause a mail arriving at server 1 to be sent to server 2, which
will then send it to server 3. Server 3 will attempt to send it back to
server 1 which will already have it, and so this will terminate the loop.
This is obviously going to create a bit of extra load, but I don't want
to try it without some advice, and I'm not sure if the replication will
be triggered properly by an email which is itself arriving via
replication. Reading the description of the components, I think it
should, since the aggregator service shouldn't care how an email has
arrived, since it is simply reading the log, right?
If a server fails, or needs to be taken out manually, I'll obviously
need to reconfigure the loop, essentially taking it back to a standard
two-server configuration. Similarly, I should be able to add a fourth
server, and so on, if I wanted.
I'm planning to distribute incoming emails over all servers, so that
these will arrive and be stored on a working server during an outage
without any reconfiguration, and to use something like nginx as a proxy
to send each user to a specific server, to distribute the client load.
Thanks in advance,
James
