We have a PostgreSQL 11.5.6 database running on VM.
RAM - 48GB
CPU - 6 cores
Disk - SSD on SAN
We wanted to check how the WAL disk is performing using pg_test_fsync.We ran a test and got around 870 ops/sec for opendatasync and fdatasync and just 430 ops/sec for fsync.We feel it is quite low as compared to what we get for local storage(2000 ops/sec for fsync).
It is not surprising to me that SAN would have higher latency than internal storage. What kind of connection do you have between your server and your SAN?
What is the recommended value for fsync ops/sec for PosgreSQL WAL disks on SAN ?
You have the hardware you have. You can't change it the same way you can change a config file entry, so I don't think that "recommended value" really applies. Is the latency of sync requests a major bottleneck for your workload? pg_test_fsync can tell you what the latency is, but can't tell you how much you care.
From:
Gunther Schadow Date: Subject:
Is there a known bug with SKIP LOCKED and "tuple to be locked was already moved to another partition due to concurrent update"?
