Re: Running rsync backups in pg15

[Evan Rempel <erempel@xxxxxxx>]

Using pgbackrest requires that I have additional local disk space for me to stage the backup before I use my actual backup software to actually perform an off-server backup.

Incrementally forever backups means that there isn't a need to do a weekly full backup. I never have to do the 84 minutes of backup.

The same thing is true for performing restores. Pgbackrest requires a two (actually 3 if you include wal replay) stage restore. Once from my actual backup system into the staging area, and then a second to get the pgbackrest files restored to the postgresql data space. There are even more steps for pgbackrest if I have to go back to the last full backup and roll forward.

What I am hearing from everyone is that there isn't a way within postgresql to remove the requirement for keeping the session open. I will have to write scripts to handle a persistent connection for the duration of the backup 🙁

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Evan

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From: Ron Johnson <ronljohnsonjr@xxxxxxxxx>

On Thu, Nov 7, 2024 at 12:47 PM Evan Rempel <erempel@xxxxxxx> wrote:

We use a similar approach, but instead of using rsync, we use our backup software directly which is an incremental forever tool. Allows backup of TB DBs in short minutes. Switching to pgbackrest is actually a step backwards for us.

Last night's pgbackrest incremental backup of a 5.1TB database took a whopping 92 seconds.  How's that a backwards step?

Sure, the weekly full backup takes 84 minutes, but that's in so way shape or form painfully slow.

 

But as the OP states, if you have to keep the postgresql session open for the pg_start_backup and the pg_stop_backup then we will have to do a significant architectual change.

Anyone know if there is a straight forward way to allows the pg_start_backup and the pg_stop_backup to be run in different sessions?

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Evan

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From: Ron Johnson <ronljohnsonjr@xxxxxxxxx>
Sent: November 7, 2024 9:34 AM
To: pgsql-admin@xxxxxxxxxxxxxx <pgsql-admin@xxxxxxxxxxxxxx>
Subject: Re: Running rsync backups in pg15

 

On Thu, Nov 7, 2024 at 11:35 AM Murthy Nunna <mnunna@xxxxxxxx> wrote:

Hi,

 

In PG14 and earlier, there is no requirement to keep database connection while rsync is in progress. However, there is a change in PG15+ that requires rsync to be while we have the same database session open that executes SELECT pg_backup_start('label'). This change requires a rewrite of existing scripts we have.

 

Currently (pg14):

 

                In bash script (run from cron)

1. psql Select pg_start_backup
2. rsync
3. psql Select pg_stop_backup

 

In pg15 and later:

 

In bash script (run from cron)

 

psql

Select pg_start_backup

! run-rsync-script

Select pg_stop_backup

 

It can be done, but it makes it ugly to check errors and so forth that occur in the rsync script.

 

Anybody found an elegant way of doing this?

Run pgbackrest instead of rsync,

--

Death to <Redacted>, and butter sauce.

Don't boil me, I'm still alive.

<Redacted> lobster!

--

Death to <Redacted>, and butter sauce.

Don't boil me, I'm still alive.

<Redacted> lobster!