[Lustre-discuss] Fwd: I/O tests on Lustre

[Garland Jackson]

Hello all,

I have a user at the Naval Research Laboratory running Lustre on a  
Cray XD1.
I'll let his email to me tell the story, but he doesn't want to know  
if the numbers he's
observing are reasonable.

What do you say out there?  Can anyone out there tell me if his  
numbers make sense?
TIA,

--garland



Begin forwarded message:

> From:
> Date: April 17, 2008 1:27:11 PM EDT
> To:
> Cc:
> Subject: I/O tests on Lustre
>
>
>   I ran the io test that I ran on the XD1 Lustre on the ice  
> machine. This program writes data from
>   an increasing number of processors ( 1,2,4,8,16,32,64)  using MPI  
> for parallelization and then
>   reads it back.  Enough data is written so that when I read the  
> data has not been cached somewhere.
>   Data block sizes are large so my programs should be giving me  
> peak bandwidths.
>
>   My last set of results were
>   Numbers of Processes     Write Rate   Read Rate
>                                            MBs/sec     MBs/sec
>                 1                          763.7       506.4
>                 2                        1248.8       968.7
>                 4                        1298.7       782.3
>                 8                        1292.5       900.6
>               16                        1298.1       820.7
>               32                        1296.7       809.3
>               64                        1296.3       878.9
>
>
>   The thirty two process failed with a time out but everything else  
> worked ok.
>
>   My question is Do these rates look reasonable based on your  
> Lustre experience?
>
>   Also any ideas on why I might be timing out on an occasional run?
>
>               wendell
>
>

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