On Tuesday January 11, brad@xxxxxxxxxxx wrote: > G'day all, > > Just started my big raid using mdadm --update resync to ensure the parity blocks are A-OK after a > kernel panic, and I have been monitoring my Disk IO with > iostat -k 5 > > Now this is an average for a 5 second period. > I note I'm seeing about 12,456 Kilobytes/sec from each drive, but a cat /proc mdstat is giving me > 6716 Kilobytes/sec. Given I'm doing a read consistency check I would expect an mdstat speed 9/10ths > of my bulk per-drive read speed. (This array is sda -> sdj) > Am I missing something really obvious? > > Kernel 2.6.10-bk10 > > Regards, > Brad > > avg-cpu: %user %nice %sys %iowait %idle > 39.18 0.00 60.82 0.00 0.00 > > Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn > hda 0.00 0.00 0.00 0 0 > sda 97.76 12465.67 0.00 33408 0 > sdb 97.76 12465.67 0.00 33408 0 > sdc 97.76 12465.67 0.00 33408 0 So this is a 5 second sample... In 5 seconds, 33408 kB were read. That's 6681.6 kB/sec according to my calculator. So it looks like iostat is reporting something wrongly. I would look there first. NeilBrown - 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
