From: Michael Grimm <trashcan@ellael.org>
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Subject: Re: Can logical replication be a solution to my current
 MariaDB/Galera setup?
Date: Sun, 24 May 2026 16:01:17 +0200
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shammat@gmx.net wrote:
> Am 22.05.26 um 15:18 schrieb Michael Grimm:

>> I have never run a postgres server before, but I do run a mariadb
>> galera cluster [1] for storing emails by an IMAP server [2].
>> Distribution and failover is dealt by haproxy [3].
>=20
> For such a system I don't see the need for a multi-master setup =
(neither
> with Postgres nor with MariaDB).

What I didn't mention in my mail is: incoming mails at all three mail =
servers become stored into each user's mailbox  at the server they =
arrive (LMTP). In this scenario multi-master is handy.

But see below.

> For high availability you don't need multi-master. A standard
> streaming replication with a failover mechanism is completely enough
> in my opinion.

Thanks for this hint w.r.t. streaming replication.

I have made some research about this kind of cluster and come to the =
conclusion that streaming replication plus repmgr [1] will meet my =
expectations.

BUT: I will need to configure haproxy to route all IMAP and LMTP traffic =
to the "current" master, only.=20

I am hoping that this can be achieved by a customised health check plus =
routing, but I have never done that before, though.

Thanks and regards,
Michael


[1] available in the FreeBSD ports collection=