Thanks! Looks like at any rate 20MB/s is miserable for 4 X 10K SAS. What are your recommendations on that regard? Should I try software RAID0 instead? How can I tell if it's the controller or disks itself is a problem? Thanks for your help! On Wed, Apr 20, 2011 at 12:19 PM, Joe Landman <landman at scalableinformatics.com> wrote: > On 04/20/2011 03:05 PM, Mohit Anchlia wrote: >> >> Like I mentioned several times my tests are running concurrent threads >> and doing concurrent writes. So overall throughput per sec should be >> atleast 20 X 3 = 60 MB/s. > > Get a copy of fio installed (yum install fio), and use the following as an > input file to it. ?Call it sw_.fio > > [sw] > rw=write > size=10g > directory=/data/mnt-stress > iodepth=32 > direct=0 > blocksize=512k > numjobs=12 > nrfiles=1 > ioengine=vsync > loops=1 > group_reporting > create_on_open=1 > create_serialize=0 > > > run this as > > ? ? ? ?fio sw_.fio > > then use the following as sr_.fio > > [sw] > rw=read > size=10g > directory=/data/mnt-stress > iodepth=32 > direct=0 > blocksize=512k > numjobs=12 > nrfiles=1 > ioengine=vsync > loops=1 > group_reporting > create_on_open=1 > create_serialize=0 > > run this as > ? ? ? ?echo 3 > /proc/sys/vm/drop_caches # note the space after "3" > ? ? ? ?fio sr_.fio > > This will run 12 simultaneous IOs, and theoretically distribute across most > of your nodes (with some oversubscription). ?Please report back the WRITE: > and READ: portions. > > Run status group 0 (all jobs): > ?WRITE: io=122694MB, aggrb=2219.5MB/s, minb=2272.8MB/s, maxb=2272.8MB/s, > mint=55281msec, maxt=55281msec > > Run status group 0 (all jobs): > ? READ: io=122694MB, aggrb=1231.4MB/s, minb=1260.9MB/s, maxb=1260.9MB/s, > mint=99645msec, maxt=99645msec > > fio is one of the best load generators out there, and I'd strongly urge you > to leverage it for your tests. > > > > -- > Joseph Landman, Ph.D > Founder and CEO > Scalable Informatics Inc. > email: landman at scalableinformatics.com > web ?: http://scalableinformatics.com > ? ? ? http://scalableinformatics.com/sicluster > phone: +1 734 786 8423 x121 > fax ?: +1 866 888 3112 > cell : +1 734 612 4615 >
