On Thu, Mar 2, 2017 at 3:51 PM, Pietro Pugni <pietro.pugni@xxxxxxxxx> wrote: > The HBA provided slightly better performance without removing the expander > and even more slightly faster after removing the expander, but then I tried > increasing numjob from 1 to 16 (tried also 12, 18, 20, 24 and 32 but found > 16 to get higher iops) and the benchmarks returned expected results. I guess > how this relates with Postgres.. probably effective_io_concurrency, as > suggested by Merlin Moncure, should be the counterpart of numjob in fio? Kind of. effective_io_concurrency allows the database to send >1 filesystem commands to the hardware from a single process. Sadly, only certain classes of query can currently leverage this factility -- as you can see, it's a huge optimization. merlin -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
