Hello, Inaam-san,
> There are four IO schedulers in Linux. Anticipatory, CFQ (default), deadline, and noop. For typical OLTP type loads generally deadline is recommended. If you are constrained on CPU and you have a good controller then its better to use noop.
> Deadline attempts to merge requests by maintaining two red black trees in sector sort order and it also ensures that a request is serviced in given time by using FIFO. I don't expect it to do the magic but was wondering that it may dilute the issue of fsync() elbowing out WAL writes.
> You can look into /sys/block/<device>/queue/scheduler to see which scheduler you are using.
Thank you for your information.
I could only find the following files in /sys/block/<device>/queue/:
iosched
max_hw_sectors_kb
max_sectors_kb
nr_requests
read_ahead_kb
In iosched, the following files exist:
quantum (the content is "4")
queued (the content is "8")