[Lustre-discuss] obdfilter-survey crashing

[Wojciech Turek]

Hi,

This chapter of the may answer your question about slow read perfoamnce

23.3.2 Write Performance Better Than Read Performance
http://wiki.lustre.org/manual/LustreManual20_HTML/LustreTroubleshooting.html#50548790_pgfId-1294879

Wojciech

On 4 January 2011 20:14, robert <spam.robert at risefx.com> wrote:
> Hi Everyone!
>
> I just setup a lustre system on centos 5.5 and lustre 1.8.5. there are
> three identical oss with four osts each.
>
> After having fantastic write rates but low read rates, I ran the
> obdfilter-survey script to get a hint of what may cause this.
>
> Unfortnately obdfilter-survey in case=disk mode freezes on two of my
> three oss at the write task of the 4 objs, 16 threads line and leaves
> the system in an unstable state requiring a reboot. The other oss runs
> through the script without problems. To exclude a problem in the
> system´s setup, I booted one of the bad oss with the working oss´ disk -
> with the same faulty result. Creating a new filesystem on all osts of
> one of the problem oss neither did the trick.
>
> Any ideas what may cause this behavior? Thanks!
>
> Robert
>
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-- 
Wojciech Turek

Senior System Architect

High Performance Computing Service
University of Cambridge