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

[Andreas Dilger]

On May 14, 2008  16:14 -0400, Garland Jackson wrote:
> 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?

It's completely dependent upon the hardware configuration (OSTs, disks,
etc).  Some customers have 50GB/s filesystems, while I have a 40MB/s
Lustre filesystem at home.

> 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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Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.