AB_ba# wrote: > I searched the complete PostgreSQL Documentation but didn't get anything with respect to IO scheduler recommendation. > What is being recommended by PostgreSQL ?
There is no clear recommendation.
I personally have seen workloads where changing from "cfq" to "deadline" or "noop" improved performance by a factor of 4, but on many systems "cfq" seems to be doing at least as good as the others.
I believe that it depends a lot on your hardware configuration and your workload, and you are best advised to run a realistic load test.
> Which is the best IO scheduler considering the Data is hosted on NFS?
No idea - probably depends on what is behind the NFS.
Make sure to use hard, fg mounts. If you can, use "jumbo frames" so that an 8KB block can fit into a single IP frame.