From: norbert poellmann <np@ibu.de>
To: pgsql-admin@lists.postgresql.org
Subject: Would you ever recommend Shared Disk Failover for HA?
Date: Thu, 22 Feb 2024 20:34:55 +0100
Message-ID: <20240222185937.M23609@ibu.de> (raw)
Admins,
https://www.postgresql.org/docs/current/different-replication-solutions.html
is listing a shared disk solution for HA.
It also mentions, "that the standby server should never access the shared storage while the primary server is running."
In a datacenter, where we have postgresql servers running on vmware VMs, the shared disk configuration sounds like an appealing solution: simple configuration, single server at a given time, simple fail-over, fully non-or-nothing write mechanics, no hazzle with replication_slots during/after failover, etc...
But "Attempts to use PostgreSQL in multi-master shared storage configurations will result in extremely severe data corruption" (https://wiki.postgresql.org/wiki/Shared_Storage).
So it seems to me, getting the comfort of a single server solution, which, in a failover, gets replaced by another single server, is paid by getting the low risk of high damage.
I know of the provisions of fencing, STONITH, etc. - but in practise, what is a robust solution?
For example: How can I STONITH a node while having network problems?
Whithout reaching the host, I cannot shoot it, nor shut it.
I also cannot wait for it get visible in the network again: another client might have interfered and commited a transaction upon the retired master server, faster than I can do some fencing/stonith or whatever.
Would you share your opinions or practical business experiences on this topic?
Thanks a lot
cheers
Norbert Poellmann
--
Norbert Poellmann EDV-Beratung email : np@ibu.de
Severinstrasse 5 telefon: 089 38469995
81541 Muenchen, Germany telefon: 0179 2133436
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-admin@postgresql.org
Cc: np@ibu.de, pgsql-admin@lists.postgresql.org
Subject: Re: Would you ever recommend Shared Disk Failover for HA?
In-Reply-To: <20240222185937.M23609@ibu.de>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox