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 0.00Device: 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 sdd 97.76 12465.67 0.00 33408 0 sde 97.76 12465.67 0.00 33408 0 sdf 98.51 12465.67 0.00 33408 0 sdg 98.51 12465.67 0.00 33408 0 sdh 98.88 12465.67 0.00 33408 0 sdi 107.09 12465.67 0.00 33408 0 sdj 104.85 12465.67 0.00 33408 0 sdk 3.73 5.97 10.45 16 28 sdl 4.10 11.94 5.97 32 16 sdm 5.22 14.93 7.46 40 20 md0 0.00 0.00 0.00 0 0 md2 8.58 26.87 7.46 72 20
srv:/home/brad# cat /proc/mdstat Personalities : [raid0] [raid5] [raid6] md2 : active raid5 sdl[0] sdm[2] sdk[1] 488396800 blocks level 5, 128k chunk, algorithm 2 [3/3] [UUU]
md0 : active raid5 sda1[0] sdj1[9] sdi1[8] sdh1[7] sdg1[6] sdf1[5] sde1[4] sdd1[3] sdc1[2] sdb1[1]
2206003968 blocks level 5, 128k chunk, algorithm 0 [10/10] [UUUUUUUUUU]
[===>.................] resync = 17.4% (42765824/245111552) finish=501.9min speed=6716K/sec
unused devices: <none>
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