Hello,
I have two raid5 arrays spanning a number of USB drives. Yesterday, I
unintentionally unplugged one of them while connecting another device
to the same hub. The drive I unplugged used to be /dev/sdh, but when I
plugged it back in, it became /dev/sdi. For md0, this didn't matter. I
re-added it and it performed a rebuild* which completed successfully.
md1, which used to consist of sde2 and sdh2, should now contain sde2
and sdi2. For some reason, though, the rebuild doesn't start when I add
sdi2. It seems md doesn't recognize sdi2 as the same device that used
to be sdh2. Is that correct? How can I tell md about the name change?
Thanks,
Oliver
[*] Bitmaps are enabled on both arrays, so I was somewhat surprised
about the full rebuild; isn't that what bitmaps are supposed to prevent?
$ mdadm /dev/md1 -a /dev/sdi2
mdadm: re-added /dev/sdi2
$ cat /proc/mdstat
[...]
md1 : active raid5 sdi2[0](F) sde2[2]
488375808 blocks super 1.1 level 5, 64k chunk, algorithm 2 [2/1] [_U]
bitmap: 0/8 pages [0KB], 32768KB chunk
$ mdadm -D /dev/md1
/dev/md1:
Version : 1.01
Creation Time : Sun Apr 12 14:19:47 2009
Raid Level : raid5
Array Size : 488375808 (465.75 GiB 500.10 GB)
Used Dev Size : 488375808 (465.75 GiB 500.10 GB)
Raid Devices : 2
Total Devices : 2
Preferred Minor : 1
Persistence : Superblock is persistent
Intent Bitmap : Internal
Update Time : Tue Aug 11 01:40:15 2009
State : active, degraded
Active Devices : 1
Working Devices : 1
Failed Devices : 1
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 64K
Name : quassel:1 (local to host quassel)
UUID : e9226e7f:cbdad2a1:481ce05b:9444d71d
Events : 106
Number Major Minor RaidDevice State
0 0 0 0 removed
2 8 66 1 active sync /dev/sde2
0 8 130 - faulty spare /dev/sdi2
$ mdadm -E /dev/sde2
/dev/sde2:
Magic : a92b4efc
Version : 1.1
Feature Map : 0x1
Array UUID : e9226e7f:cbdad2a1:481ce05b:9444d71d
Name : quassel:1 (local to host quassel)
Creation Time : Sun Apr 12 14:19:47 2009
Raid Level : raid5
Raid Devices : 2
Avail Dev Size : 976751736 (465.75 GiB 500.10 GB)
Array Size : 976751616 (465.75 GiB 500.10 GB)
Used Dev Size : 976751616 (465.75 GiB 500.10 GB)
Data Offset : 264 sectors
Super Offset : 0 sectors
State : clean
Device UUID : 0fcc7d6d:0ec92b47:c371f8e6:bd7d2cac
Internal Bitmap : 2 sectors from superblock
Update Time : Tue Aug 11 01:40:18 2009
Checksum : 4290b585 - correct
Events : 108
Layout : left-symmetric
Chunk Size : 64K
Array Slot : 2 (failed, failed, 1)
Array State : _U 2 failed
$ mdadm -E /dev/sdi2
/dev/sdi2:
Magic : a92b4efc
Version : 1.1
Feature Map : 0x1
Array UUID : e9226e7f:cbdad2a1:481ce05b:9444d71d
Name : quassel:1 (local to host quassel)
Creation Time : Sun Apr 12 14:19:47 2009
Raid Level : raid5
Raid Devices : 2
Avail Dev Size : 976751736 (465.75 GiB 500.10 GB)
Array Size : 976751616 (465.75 GiB 500.10 GB)
Used Dev Size : 976751616 (465.75 GiB 500.10 GB)
Data Offset : 264 sectors
Super Offset : 0 sectors
State : clean
Device UUID : 5ba69d85:c46d6bb0:bf71606e:2877b067
Internal Bitmap : 2 sectors from superblock
Update Time : Mon Aug 10 15:32:23 2009
Checksum : 6db9f21 - correct
Events : 28
Layout : left-symmetric
Chunk Size : 64K
Array Slot : 0 (failed, failed, 1)
Array State : _u 2 failed
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