Hello, list,
I found something interesting when i try to create a brand new array on
brand new drives....
1. The command was:
mdadm --create /dev/md1 --level=5 --raid-devices=12 --chunk=1024 \
/dev/hda2 /dev/hdb2 /dev/hdc2 /dev/hdd2 \
/dev/sda2 /dev/sdb2 /dev/sdc2 /dev/sdd2 \
/dev/sde2 /dev/sdf2 /dev/sdg2 /dev/sdh2
2. The proc/mdstat:
Personalities : [linear] [raid0] [raid1] [raid5] [multipath] [raid6]
[raid10] [f
aulty]
md1 : active raid5 sdh2[12] sdg2[10] sdf2[9] sde2[8] sdd2[7] sdc2[6] sdb2[5]
sda
2[4] hdd2[3] hdc2[2] hdb2[1] hda2[0]
2148934656 blocks level 5, 1024k chunk, algorithm 2 [12/11]
[UUUUUUUUUUU_]
[=>...................] recovery = 5.7% (11308928/195357696)
finish=234.
3min speed=13088K/sec
unused devices: <none>
3. The mdadm -D
/dev/md1:
Version : 00.90.02
Creation Time : Sat Dec 31 12:59:51 2005
Raid Level : raid5
Array Size : 2148934656 (2049.38 GiB 2200.51 GB)
Device Size : 195357696 (186.31 GiB 200.05 GB)
Raid Devices : 12
Total Devices : 12
Preferred Minor : 1
Persistence : Superblock is persistent
Update Time : Sat Dec 31 12:59:51 2005
State : clean, degraded, recovering
Active Devices : 11
Working Devices : 12
Failed Devices : 0
Spare Devices : 1
Layout : left-symmetric
Chunk Size : 1024K
Rebuild Status : 6% complete
UUID : 03cbaf43:19a629d2:0886920c:a696f7af
Events : 0.1
Number Major Minor RaidDevice State
0 3 2 0 active sync /dev/hda2
1 3 66 1 active sync /dev/hdb2
2 22 2 2 active sync /dev/hdc2
3 22 66 3 active sync /dev/hdd2
4 8 2 4 active sync /dev/sda2
5 8 18 5 active sync /dev/sdb2
6 8 34 6 active sync /dev/sdc2
7 8 50 7 active sync /dev/sdd2
8 8 66 8 active sync /dev/sde2
9 8 82 9 active sync /dev/sdf2
10 8 98 10 active sync /dev/sdg2
12 8 114 11 spare rebuilding /dev/sdh2
4. The end of the dmesg
md: bind<hda2>
md: bind<hdb2>
md: bind<hdc2>
md: bind<hdd2>
md: bind<sda2>
md: bind<sdb2>
md: bind<sdc2>
md: bind<sdd2>
md: bind<sde2>
md: bind<sdf2>
md: bind<sdg2>
md: bind<sdh2>
raid5: device sdg2 operational as raid disk 10
raid5: device sdf2 operational as raid disk 9
raid5: device sde2 operational as raid disk 8
raid5: device sdd2 operational as raid disk 7
raid5: device sdc2 operational as raid disk 6
raid5: device sdb2 operational as raid disk 5
raid5: device sda2 operational as raid disk 4
raid5: device hdd2 operational as raid disk 3
raid5: device hdc2 operational as raid disk 2
raid5: device hdb2 operational as raid disk 1
raid5: device hda2 operational as raid disk 0
raid5: allocated 12531kB for md1
raid5: raid level 5 set md1 active with 11 out of 12 devices, algorithm 2
RAID5 conf printout:
--- rd:12 wd:11 fd:1
disk 0, o:1, dev:hda2
disk 1, o:1, dev:hdb2
disk 2, o:1, dev:hdc2
disk 3, o:1, dev:hdd2
disk 4, o:1, dev:sda2
disk 5, o:1, dev:sdb2
disk 6, o:1, dev:sdc2
disk 7, o:1, dev:sdd2
disk 8, o:1, dev:sde2
disk 9, o:1, dev:sdf2
disk 10, o:1, dev:sdg2
RAID5 conf printout:
--- rd:12 wd:11 fd:1
disk 0, o:1, dev:hda2
disk 1, o:1, dev:hdb2
disk 2, o:1, dev:hdc2
disk 3, o:1, dev:hdd2
disk 4, o:1, dev:sda2
disk 5, o:1, dev:sdb2
disk 6, o:1, dev:sdc2
disk 7, o:1, dev:sdd2
disk 8, o:1, dev:sde2
disk 9, o:1, dev:sdf2
disk 10, o:1, dev:sdg2
disk 11, o:1, dev:sdh2
md: syncing RAID array md1
md: minimum _guaranteed_ reconstruction speed: 1000 KB/sec/disc.
md: using maximum available idle IO bandwidth (but not more than 200000
KB/sec) for reconstruction.
md: using 128k window, over a total of 195357696 blocks.
5. The question
Why shows sdh2 as spare?
The MD array size is correct.
And i really can see, the all drive is reading, and sdh2 is *ONLY* writing.
Cheers,
Janos
(Happy new year! :)
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