On Fri, 27 Jul 2012 14:45:18 -0700, you wrote: >On 07/27/2012 12:08 PM, Bill Davidsen wrote: >> Have you set the io scheduler to deadline on all members of the array? >> That's kind of "job one" on older kernels. >> > >I have not, thanks for the tip, I'll look into that now. Plus I disable the on-drive queuing (NCQ) during startup, right now I don't have benchmarks to show the difference. This on a six by 1TB drive RAID6 array I built over a year ago on Slackware64-13.37: # cat /etc/rc.d/rc.local ... # turn off NCQ on the RAID drives by adjusting queue depth to 1 n=1 echo "rc.local: Disable RAID drives' NCQ" for d in a b c d e f do echo " set NCQ depth to $n on sd${d}" echo $n > /sys/block/sd${d}/device/queue_depth done ... Maybe you could try that? See if it makes a difference. My drives are Seagate. Grant. -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html