G'day all,
Here is an interesting question( well I think so in any case ). I just replaced a failed disk in my
15 drive Raid-6.
Simply mdadm --add /dev/md0 /dev/sdl
Why, when there is no other activity on the array at all, is it writing to every disk during the
recovery? I would have assumed it just read from the others and write to sdl.
This is an iostat -k 5 on that machine while rebuilding
avg-cpu: %user %nice %sys %iowait %idle
0.00 0.00 100.00 0.00 0.00
Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn
sda 121.08 14187.95 925.30 23552 1536
sdb 127.71 14187.95 1002.41 23552 1664
sdc 125.30 14187.95 1002.41 23552 1664
sdd 122.29 14187.95 1002.41 23552 1664
sde 125.30 14187.95 1002.41 23552 1664
sdf 127.71 14187.95 1002.41 23552 1664
sdg 125.90 14187.95 925.30 23552 1536
sdh 125.30 14187.95 925.30 23552 1536
sdi 134.34 14187.95 925.30 23552 1536
sdj 137.95 14187.95 925.30 23552 1536
sdk 140.36 14187.95 1850.60 23552 3072
sdl 79.52 0.00 14265.06 0 23680
sdm 133.13 14187.95 925.30 23552 1536
sdn 134.34 14187.95 925.30 23552 1536
sdo 133.73 14187.95 925.30 23552 1536
md0 0.00 0.00 0.00 0 0
storage1:/home/brad# cat /proc/mdstat
Personalities : [raid6]
md0 : active raid6 sdl[15] sdg[6] sda[0] sdo[14] sdn[13] sdm[12] sdk[10] sdj[9] sdi[8] sdh[7] sdf[5]
sde[4] sdd[3] sdc[2] sdb[1]
3186525056 blocks level 6, 128k chunk, algorithm 2 [15/14] [UUUUUUUUUUU_UUU]
[>....................] recovery = 1.8% (4518144/245117312) finish=838.3min speed=4782K/sec
unused devices: <none>
Regards,
Brad
--
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