Thank you. I was thinking along the same lines, but I am not sure I understand why the setup will fall apart on failover. If I also have archive_mode always on the primary site, I think that I just need to pg_rewind (or PITR restore) old primary and configure it as a secondary to the new master followed by a local backup. Am I missing something obvious?
Regards, Radu On Mon, Nov 10, 2025 at 5:33 PM Greg Sabino Mullane <[email protected]> wrote: > What you are asking for is tricky, but possible. You can setup two repos, > one for each server. On the first server (in datacenter A), you have a > "normal" pgbackrest configuration, with an explicit backup-standby=n. pg1-* > points to the local server, pg2-* points to the replica. The repo is in > datacenter A.Backups run from PG server in datacenter A, to the backrest > repo in datacenter A. WAL is archived from A -> A > > On datacenter B, you have a separate local repo, a different stanza name, > and within that stanza, you have backup-standby=y, pg1 pointing to the > local pg, pg2 pointing back to A. In the postgresql.conf, your > archive-command pushes to this second repo, and archive_mode is "always". > Backups run from the PG server in datacenter A, but 99% of the files are > actually copied from the replica in datacenter B, and goes to the backrest > server in datacenter B. WAL is archived from B -> B. > > That's the basic idea. It falls apart rapidly if this second data center > ever fails over. > Cheers, > Greg > > -- > Crunchy Data - https://www.crunchydata.com > Enterprise Postgres Software Products & Tech Support > >
