Re: Linux Raid performance

[Learner Study <learner.study@gmail.com>]

Hi Keld:

Thanks for your email...

1. Can you pls point me to this benchmark (which shows 500MB/s)? I
would like to know which CPU, HDDs and kernel version used to achieve
this...

2. Secondly, I would like to understand how raid stack (md driver)
scales as we add more cores...if single core gives ~500MB/s, can two
core give ~1000MB/s? can four cores give ~2000MB/s? etc....

Thanks for your time.

On Fri, Apr 2, 2010 at 4:05 AM, Keld Simonsen <keld@keldix.com> wrote:
> 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
>> >
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html