Thread: Pgbackrest backup is too slow

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Greetings,

* Ajay Pratap (ajaypratap@ameyo.com) wrote:
> I have a Centos 7 server which runs Postgresql 10.7. I am using pgbackrest
> to take db backup.
> Problem is backup is too slow.

Have you tried running 'top' to see what's going on?

> My data dir size is 9.6G and full backup runtime is 22 mins
> I also tried using process-max=3, full backup runtime = 21 mins

Erm, those numbers don't make any sense to me- as an example, we
regularly back up a 12GB database, from Dallas to San Fran, in 5
minutes.

I see you're requesting a checkpoint to start immediately, but how long
does the checkpoint actually take to complete?  Have you looked at your
PG logs..?

Have you tried running 'top' and then running the backup and looked to
see what's going on?  Is the CPU at 100%?  Are all the processes stuck
in 'D' state all the time (meaning you don't have enough i/o resources),
or...?

> In production we have a database of size more than 500GB. It would not be
> feasible for me to use it as it is.pgbackrest version is
> 2.18-1.rhel7.x86_64.
> installed from pgdg yum repo.

Given sufficient resources, we've seen pgbackrest push over 1TB/hour, so
there is definitely something strange going on here.

Thanks,

Stephen

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Stephen Frost <sfrost@snowman.net> wrote on 2019/10/11 08:50:53 AM:

> From: Stephen Frost <sfrost@snowman.net>
> To: Ajay Pratap <ajaypratap@ameyo.com>
> Cc: Postgres General <pgsql-general@postgresql.org>
> Date: 2019/10/11 08:51 AM
> Subject: [EXTERNAL] Re: Pgbackrest backup is too slow
>
> Greetings,
>
> * Ajay Pratap (ajaypratap@ameyo.com) wrote:
> > I have a Centos 7 server which runs Postgresql 10.7. I am using pgbackrest
> > to take db backup.
> > Problem is backup is too slow.
>
> Have you tried running 'top' to see what's going on?
>
> > My data dir size is 9.6G and full backup runtime is 22 mins
> > I also tried using process-max=3, full backup runtime = 21 mins
>
> Erm, those numbers don't make any sense to me- as an example, we
> regularly back up a 12GB database, from Dallas to San Fran, in 5
> minutes.


How many database objects do you have?  For databases with a lot of tables and/or indexes (think tens of thousands), backup performance will slow down.  This has improved a lot in newer versions, but still impacts performance of the backups.

Brad.

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