odd behavior of google cloud machine
I created a machine in google cloud with below.
DB SIZE : 100GB
CPU : 8 vCPUs
RAM : 30 GB
DISK : Standard persistent disk
DB VERSION : PostgreSQL 9.3
When I am checking for time estimation for a 100GB database I am getting different times. There is no processes other then the database and I am the only user using it..
Time for taking base backup first time
plain format : 31m55.348s
[postgres@old-server bin]$ time pg_basebackup –pgdata=/tmp/BACKUP –format=p –xlog-method=stream
real 31m55.348s
user 0m12.418s
sys 1m45.688s
compressed format : 29m47.282s
[postgres@old-server tmp]$ time pg_basebackup -D /tmp/BACKUP –format=t –compress=9 –gzip
NOTICE: pg_stop_backup complete, all required WAL segments have been archived
real 29m47.282s
user 27m44.429s
sys 0m38.565s
Compressed format takes more time in normal scenarios but here it is reverse, the compressed format is taking less time.
I have tried the same base backup with xlog-method stream and with out stream. This time the backup time got doubled.
[postgres@old-server ~]$ time pg_basebackup –pgdata=/tmp/BACKUPWithout stream
NOTICE: pg_stop_backup complete, all required WAL segments have been archived
real 61m2.175s
user 0m16.302s
sys 2m11.380s
[postgres@old-server ~]$ time pg_basebackup –pgdata=/tmp/BACKUP –format=p –xlog-method=stream
real 54m38.801s
user 0m15.629s
sys 2m10.309s
DB SIZE : 100GB
CPU : 8 vCPUs
RAM : 30 GB
DISK : Standard persistent disk
DB VERSION : PostgreSQL 9.3
When I am checking for time estimation for a 100GB database I am getting different times. There is no processes other then the database and I am the only user using it..
Time for taking base backup first time
plain format : 31m55.348s
[postgres@old-server bin]$ time pg_basebackup –pgdata=/tmp/BACKUP –format=p –xlog-method=stream
real 31m55.348s
user 0m12.418s
sys 1m45.688s
compressed format : 29m47.282s
[postgres@old-server tmp]$ time pg_basebackup -D /tmp/BACKUP –format=t –compress=9 –gzip
NOTICE: pg_stop_backup complete, all required WAL segments have been archived
real 29m47.282s
user 27m44.429s
sys 0m38.565s
Compressed format takes more time in normal scenarios but here it is reverse, the compressed format is taking less time.
I have tried the same base backup with xlog-method stream and with out stream. This time the backup time got doubled.
[postgres@old-server ~]$ time pg_basebackup –pgdata=/tmp/BACKUPWithout stream
NOTICE: pg_stop_backup complete, all required WAL segments have been archived
real 61m2.175s
user 0m16.302s
sys 2m11.380s
[postgres@old-server ~]$ time pg_basebackup –pgdata=/tmp/BACKUP –format=p –xlog-method=stream
real 54m38.801s
user 0m15.629s
sys 2m10.309s
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