Re: Linux Raid performance

[Keld Simonsen <keld@keldix.com>]

On Thu, Apr 01, 2010 at 08:07:25PM -0700, Learner Study wrote:
> Hi Keld:
> 
> Do we have raid5/6 numbers for linux on any multi-core CPU? Most of
> the benchmarks I have seen on wiki show raid5 perf to be ~150MB/s with
> single core CPUs. How does that scale with multiple cores? Something
> like intel's jasper forest???

I have not checked if the benchmarks were on multi core machines. 
It should not matter much if there were more than one CPU, but
of cause it helps a little. bonnie++ test reports cpu usage, and this
is not insignificant, say in the 20 -60 % range for some tests,
but nowhere near a bottleneck. There was one with a raid5 performance
seq read of about 500 MB/s with 36 % cpu utilization, so it is
definitely possible to come beyound 150 MB/s. The speed is largely
dependent on number of disk drives you employ.


> If available, can u pls point me to numbers with multi-core CPU?

I dont have such benchmarks AFAIK. But new benchmarks are always welcome,
so please feel free to submit your findings.

Best regards
keld

> Thanks!
> 
> On Wed, Mar 31, 2010 at 1:15 PM, Keld Simonsen <keld@keldix.com> wrote:
> > On Wed, Mar 31, 2010 at 12:42:57PM -0700, Learner Study wrote:
> >> Hi Linux Raid Experts:
> >>
> >> I was looking at following wiki on raid perf on linux:
> >>
> >> https://raid.wiki.kernel.org/index.php/Performance
> >>
> >> and notice that the performance numbers are with 2.6.12 kernel.
> >>
> >> Do we perf numbers for:
> >> - latest kernel (something like 2.6.27 / 2.6.31)
> >> - raid 5 and 6
> >>
> >> Can someone please point me to appropriate link?
> >
> > The link mentioned above has a number of other performance reports, for other levels of the kernel.
> > Anyway you should be able to get comparable results for newer kernels, the kernel has not become
> > slower since 2.6.12 on RAID.
> >
> > best regards
> > Keld
> >
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