[Lustre-discuss] Where to run PIOS

[Atul Vidwansa]

Hello Wang,

PIOS is designed for writing to POSIX filesystem or block devices. So, 
you can run it on block devices on OSS or on Lustre clients. Running it 
on Lustre clients will give you better understanding of the performance 
you will get for your application.

For example, if lustre is mounted at  /mnt/lustre on a client node, then:
1] For writing single shared file:
./pios -t 4,8,16,32,64 -n 8192 -c 1M -s 1M -o 1M -p /mnt/lustre

2] For writing files per process/thread:
./pios -t 4,8,16,32,64 -n 8192 -c 1M -s 1M -o 1M --load=fpp -p /mnt/lustre

Total amount of data written is product of number of regions (-n) and 
regionsize (-s). Make sure you are writing at least twice the size of 
memory on Lustre client. You can experiment with different value of 
chunksize (-c) to find best performance for your workload.

Cheers,
_Atul

Wang lu wrote:
> Dear list,
>    
> May I ask where can I run PIOS command? I think to determine the max thread
> number of OSS, it should be run on OSS, however, the OST directorys are
> unwritable. Can I write to /dev/sdaX? I am confused. 
>
> Sorry, I have to open a new topic because I make last one too long...
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>   


-- 
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Atul Vidwansa
Sun Microsystems Australia Pty Ltd
Web: http://blogs.sun.com/atulvid
Email: Atul.Vidwansa at Sun.COM