Message-ID: <99815bc4cd2622115ea417f6f1e3ceebf8a5247e.camel@cybertec.at>
Subject: Re: pg15 and VM snapshots with pg_backup_start
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: oernii+pg@axonpro.sk, pgsql-admin@lists.postgresql.org
Date: Thu, 30 Mar 2023 12:45:39 +0200
In-Reply-To: <1bd4e56c-f6ad-f711-255a-4432b5f20a62@axonpro.sk>
References: <1bd4e56c-f6ad-f711-255a-4432b5f20a62@axonpro.sk>
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On Thu, 2023-03-30 at 11:50 +0200, oernii+pg@axonpro.sk wrote:
> Hi, we run a lot of PG14 and lower. We do VM snapshots, which we backup.
> Before the snapshot we run a quiesce script which also runs pg_start_back=
up().
> After a few seconds the snapshot if finished and we call pg_stop_backup.
> This is working file for us, but pg15 removed this function and replaced =
it
> with pg_backup_start(), which however requires the session to be open, ot=
herwise we get:
> =C2=A0=C2=A0=C2=A0 WARNING:=C2=A0 aborting backup due to backend exiting =
before pg_backup_stop was called
>=20
> For pg15 do I need to keep the session open, will the snapshot contain un=
corruped data?

If the snapshot is atomic, that is, represents a state that the file system=
 had
at sume point in time, PostgreSQL can always use it for recovery.

Otherwise, you cannot use this backup, because you only get "backup_label" =
from
"pg_backup_stop()", and without "backup_label", you cannot recover the back=
up.

In the latter case, you may find this useful:
https://github.com/cybertec-postgresql/safe-backup

Yours,
Laurenz Albe