On 2016-05-25 19:13, Kelly Lesperance wrote: > Hdparm didn’t get far: > > [root@r1k1 ~] # hdparm -tT /dev/sda > > /dev/sda: > Timing cached reads: Alarm clock > [root@r1k1 ~] # Hi Kelly, Try running 'iostat -xdmc 1'. Look for a single drive that has substantially greater await than ~10msec. If all the drives except one are taking 6-8msec, but one is very much more, you've got a drive that drags down the whole array's performance. Ignore the very first output from the command - it's an average of the disk subsystem since boot. Post a representative output along with the contents /proc/mdstat. Good luck, -- Charles Polisher _______________________________________________ CentOS mailing list CentOS@xxxxxxxxxx https://lists.centos.org/mailman/listinfo/centos