On 12/14/2010 03:33 PM, Brock Palen wrote:
> Is there a safe way to test block device read performance while
> lustre is using the device? Example a type of read only access to
> the device to check that it is performing correctly?
Brock
We allocate a small aligned partition before the Lustre OST partition
for read and write testing. If you don't have this, you might be able
to do read testing. The latter you would need to do with dd on the raw
device
dd if=/dev/sdXP of=/dev/null bs=128k count=Z
where X is the drive, P is the partition number (if any), and Z is the
number of 128k blocks you want to read. Don't mix up if and of
arguments (e.g. this can be a dangerous command with a minor typo)
>
> Or is this a bad idea?
It will impact OST performance if you wind up increasing resource
contention.
Regards,
Joe
>
> Brock Palen www.umich.edu/~brockp Center for Advanced Computing
> [email protected] (734)936-1985
>
>
>
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Scalable Informatics Inc.
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