On Mon, Jun 29, 2020 at 5:27 AM Nikhil Shetty <nikhil.db...@gmail.com> wrote:
> Hi Team, > > 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. Cheers, Jeff >
