On Dec 14, 2010, at 3:37 PM, Joe Landman wrote: > 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
This is what I thought I could try, we have just seen a degration in performance on our OST's and trying to track down why. Thanks > > 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. Figured Thanks > > Regards, > > Joe > >> >> Brock Palen www.umich.edu/~brockp Center for Advanced Computing >> [email protected] (734)936-1985 >> >> >> >> _______________________________________________ Lustre-discuss >> mailing list [email protected] >> http://lists.lustre.org/mailman/listinfo/lustre-discuss > > > -- > Joseph Landman, Ph.D > Founder and CEO > Scalable Informatics Inc. > email: [email protected] > web : http://scalableinformatics.com > http://scalableinformatics.com/sicluster > phone: +1 734 786 8423 x121 > fax : +1 866 888 3112 > cell : +1 734 612 4615 > _______________________________________________ > Lustre-discuss mailing list > [email protected] > http://lists.lustre.org/mailman/listinfo/lustre-discuss > > _______________________________________________ Lustre-discuss mailing list [email protected] http://lists.lustre.org/mailman/listinfo/lustre-discuss
