Обсуждение: Pgbackrest info output interpretation
Hi,
/data/edb/as16
[root@db1 as16]# du -h -d 1
5.3G ./data
25G ./tablespace
30G .
[root@db1 as16]#
I am having confusion trying to understand the database size, backupsize and repo backup size..
In my DB server I have du output as follows.
/data/edb/as16
[root@db1 as16]# du -h -d 1
5.3G ./data
25G ./tablespace
30G .
[root@db1 as16]#
On my Repo Server pgbackest info says ....
full backup: 20251114-121504F
timestamp start/stop: 2025-11-14 12:15:04+05:30 / 2025-11-14 12:20:58+05:30
wal start/stop: 000000010000000500000024 / 000000010000000500000024
database size: 3GB, database backup size: 3GB
repo1: backup size: 431.0MB
Could someone shed some light on 431 MB and database size:3GB, database backup size : 3GB compared to the DB cluster on disk usage output ?
How to correlate the pgbackrest ( info) database size, database backup size and repo1 backup size and actual du output on DB cluster.
timestamp start/stop: 2025-11-14 12:15:04+05:30 / 2025-11-14 12:20:58+05:30
wal start/stop: 000000010000000500000024 / 000000010000000500000024
database size: 3GB, database backup size: 3GB
repo1: backup size: 431.0MB
Could someone shed some light on 431 MB and database size:3GB, database backup size : 3GB compared to the DB cluster on disk usage output ?
How to correlate the pgbackrest ( info) database size, database backup size and repo1 backup size and actual du output on DB cluster.
Note: I am using zst compression on pgbackrest
Regards,
Krishane
On Fri, Nov 14, 2025 at 3:27 AM KK CHN <kkchn.in@gmail.com> wrote:
Hi,I am having confusion trying to understand the database size, backupsize and repo backup size..In my DB server I have du output as follows.
/data/edb/as16
[root@db1 as16]# du -h -d 1
5.3G ./data
25G ./tablespace
30G .
[root@db1 as16]#On my Repo Server pgbackest info says ....full backup: 20251114-121504F
timestamp start/stop: 2025-11-14 12:15:04+05:30 / 2025-11-14 12:20:58+05:30
wal start/stop: 000000010000000500000024 / 000000010000000500000024
database size: 3GB, database backup size: 3GB
repo1: backup size: 431.0MB
Could someone shed some light on 431 MB and database size:3GB, database backup size : 3GB compared to the DB cluster on disk usage output ?
How to correlate the pgbackrest ( info) database size, database backup size and repo1 backup size and actual du output on DB cluster.
Do you have the job log at "detail" level? That lists every file which is backed up. Sadly, no compression rates.
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The "database size" is going to be your data directory, MINUS your pg_wal directory, MINUS unlogged/temp relations, and MINUS things that are not needed for recovery (i.e. all the small pg_ directories such as pg_subtrans). The "database backup size" is how much of that 3GB is part of *this* backup - for a full backup, the number will be the same, for diff or incr, it will be a lot less. The "repo backup size" on the last line is the compressed size of the previous "database backup size"
How to correlate the pgbackrest ( info) database size, database backup size and repo1 backup size and actual du output on DB cluster.
You cannot, really, without deep knowledge of things like which files on disk map back to unlogged tables. However, du on the datadir minus all pg_ dirs should get you in the ballpark. As a quick example:
cd $DATADIR
du --summarize * | awk '!/pg_/{x=x+$1}END{print x}' | numfmt --to=iec
Cheers,
Greg
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