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.

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

Hello Stephen,
Thanks for your prompt response.
As recommended by you, I will try to isolate the problem at system level,
Meanwhile, Is there any system recommendation by pgbackrest, (how much
process-max should be configured) should I set affinity to pgbackrest
process, how many core should be kept for backup /restore. Or any other
configuration?

My DB size is 500GB and increasing .

Regards,
Ajay

On Fri, Oct 11, 2019 at 6:20 PM Stephen Frost <sfrost@snowman.net> wrote:

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.

Thanks for your previous replies.
It turns out my machine was having kernel Issues, which made it slow.
I setup another cluster in different machine now I could able to backup 42G
in 6 min(s).
<EOM>

On Fri, Oct 11, 2019 at 7:23 PM Brad Nicholson <bradn@ca.ibm.com> wrote:

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.

--

*Disclaimer:* The information in this communication is confidential and
may be legally privileged. It is intended solely for the use of the
individual or entity to whom it is addressed and others authorized to
receive it. If you are not the intended recipient you are hereby notified
that any disclosure, copying, distribution or taking action in reliance of
the contents of this information is strictly prohibited and may be
unlawful. Drishti is neither liable for the improper, incomplete
transmission of the information contained in this communication nor any
delay in its receipt. The communication is not intended to operate as an
electronic signature under any applicable law. Drishti assumes no
responsibility for any loss or damage resulting from the use of e-mails.