On Thu, Feb 22, 2024 at 2:35 PM norbert poellmann <np@xxxxxx> wrote:
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).
Our DB servers are also VMware VMs, with the disks managed by VMware, too. If a blade dies, the VM automatically restarts on a different blade. (Heck, ESX might automagically migrate it with no downtime. I've never *known* this to happen, but I don't have access to the VMware console; they just stay up for months, getting migrated around as necessary for load management.)
