Re: [PERFORM] different io elevators in linux

[Mark Wong]

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

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Re: [PERFORM] different io elevators in linux

[Josh Berkus]

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

-- 
--Josh

Josh Berkus
Aglio Database Solutions
San Francisco

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