Re: different io elevators in linux

On Mon, Oct 25, 2004 at 10:09:17AM -0700, Josh Berkus wrote:
> Bjorn,
>
> > I haven't read much FAQs but has anyone done some benchmarks with
> > different io schedulers in linux with postgresql?
>
> According to OSDL, using the "deadline" scheduler sometimes results in a
> roughly 5% boost to performance, and sometimes none, depending on the
> application.   We use it for all testing, though, just in case.
>
> --Josh
>

Yes, we found with an OLTP type workload, the as scheduler performs
about 5% worse than the deadline scheduler, where in a DSS type
workload there really isn't much difference.  The former doing a
mix of reading/writing, where the latter is doing mostly reading.

Mark