Re: pgBackRest backup from standby

Hi Don,

On 2/19/18 10:01 AM, Don Seiler wrote:
> On Mon, Feb 19, 2018 at 8:53 AM, David Steele <david(at)pgmasters(dot)net
> <mailto:david(at)pgmasters(dot)net>> wrote:
>
> Anything *not* in global (except pg_control), base, pg_tblspc,
> pg_xact/pg_clog, and pg_multixact are copied from the primary.
>
> For example, pg_stat is copied from the primary so these stats are
> preserved on a standby backup.
>
> So if I have tablespaces outside of $PGDATA (but symlinked from within
> pg_tblspc, of course), those will still be backed up from the standby,
> right?

Correct.

> Is it right to say that the files that would be copied from primary are
> very small, typically? So it isn't a huge transfer over the WAN (in my
> case)?

Yes, they are typically very small. The general exception to this rule
is if logs are stored in pg_log. I recommend storing logs out of the
PGDATA dir as they can be quite large and don't really make sense to
restore to another server.

Files copied from the master will be marked as such in backup.manifest
(master:true) so you can check for yourself.

> I did come up with a sort of Rube Goldberg-esque workaround for now
> involving using a clone of the prod standby VM from Veeam backup to use
> as the backup source (after stopping recovery and opening it as a
> standalone DB).

You don't get PITR that way, of course, but at least it's a backup. As
long as your clone is consistent.

--
-David
david(at)pgmasters(dot)net