Hi Jeff, To avoid confusion, Hitachi Storage G900 has 41Gbps Performance bandwidth (Throughput) and 10Gbps N/W bandwidth.
Thanks and Regards, Nikhil On Wed, Jul 1, 2020 at 10:36 PM Nikhil Shetty <nikhil.db...@gmail.com> wrote: > Hi Jeff, > > Thank you for your inputs. We may stick with fdatasync for now. We will > get more details on connection details between SAN and server from the > storage team and update this thread. > > Storage is Hitachi G900 with 41Gbps bandwidth. > > Thanks and regards, > Nikhil > > > > On Tue, Jun 30, 2020 at 9:51 PM Jeff Janes <jeff.ja...@gmail.com> wrote: > >> 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 >> >>>
