High availability of Dovecot

[Stephan von Krawczynski]

On Thu, 11 Apr 2019 16:44:40 +0800
luckydog xf via dovecot <dovecot at dovecot.org> wrote:

> Hi, list,
> [...]
>    Thanks for any suggestions and ideas.
> 

Hm, it seems most of the people answering have no real experience in
production with suchs setups.
Basically do this:
- setup keepalived as a cluster director on both boxes for two VIPs where
one is master for each and backup for the other.
- configure keepalived to load-balance both servers on the services you want
(e.g. SMTP, POP3, IMAP, POP3S, IMAPS, ...)
- use a high persistence timeout so that the same client ends up mostly on the
same service/box
- you need several subnets to do this, so that your loadbalancing takes place
on another subnet (not the external VIPs, neither the same subnet)
- If either of the boxes fails, the other will take over the VIP and continue
to serve the configured mail services, load-balancing will leave out the dead
box
This _will_ work in production, I promise, but you should be experienced with
keepalived, arp, networking to do this setup.

-- 
Regards,
Stephan