> On Tue, 1 Mar 2011 17:13:09 +1000 wrote:
>
>>
>> Manual re-assembly outputs as follows:
>>
>>
>> mdadm -Ss
>>
>> mdadm: stopped /dev/md0
>>
>> ---
>>
>> mdadm -Asvvv
>>
>> mdadm: looking for devices for /dev/md/0
>> mdadm: no RAID superblock on /dev/dm-6
>> mdadm: /dev/dm-6 has wrong uuid.
>> mdadm: no RAID superblock on /dev/dm-5
>> mdadm: /dev/dm-5 has wrong uuid.
>> mdadm: no RAID superblock on /dev/dm-4
>> mdadm: /dev/dm-4 has wrong uuid.
>> mdadm: no RAID superblock on /dev/dm-3
>> mdadm: /dev/dm-3 has wrong uuid.
>> mdadm: cannot open device /dev/dm-2: Device or resource busy
>> mdadm: /dev/dm-2 has wrong uuid.
>> mdadm: no RAID superblock on /dev/dm-1
>> mdadm: /dev/dm-1 has wrong uuid.
>> mdadm: no RAID superblock on /dev/dm-0
>> mdadm: /dev/dm-0 has wrong uuid.
>> mdadm: no RAID superblock on /dev/sde
>> mdadm: /dev/sde has wrong uuid.
>> mdadm: no RAID superblock on /dev/sdd
>> mdadm: /dev/sdd has wrong uuid.
>> mdadm: cannot open device /dev/sdc7: Device or resource busy
>> mdadm: /dev/sdc7 has wrong uuid.
>> mdadm: cannot open device /dev/sdc6: Device or resource busy
>> mdadm: /dev/sdc6 has wrong uuid.
>> mdadm: cannot open device /dev/sdc5: Device or resource busy
>> mdadm: /dev/sdc5 has wrong uuid.
>> mdadm: no RAID superblock on /dev/sdc2
>> mdadm: /dev/sdc2 has wrong uuid.
>> mdadm: cannot open device /dev/sdc1: Device or resource busy
>> mdadm: /dev/sdc1 has wrong uuid.
>> mdadm: cannot open device /dev/sdc: Device or resource busy
>> mdadm: /dev/sdc has wrong uuid.
>> mdadm: no RAID superblock on /dev/sda
>> mdadm: /dev/sda has wrong uuid.
>> mdadm: no RAID superblock on /dev/sdb
>> mdadm: /dev/sdb has wrong uuid.
>> mdadm: /dev/sdd1 is identified as a member of /dev/md/0, slot 2.
>> mdadm: /dev/sda1 is identified as a member of /dev/md/0, slot 0.
>> mdadm: /dev/sdb1 is identified as a member of /dev/md/0, slot 1.
>> mdadm: added /dev/sdb1 to /dev/md/0 as 1
>> mdadm: added /dev/sdd1 to /dev/md/0 as 2
>> mdadm: looking for devices for /dev/md/0
>> mdadm: no RAID superblock on /dev/dm-6
>> mdadm: /dev/dm-6 has wrong uuid.
>> mdadm: no RAID superblock on /dev/dm-5
>> mdadm: /dev/dm-5 has wrong uuid.
>> mdadm: no RAID superblock on /dev/dm-4
>> mdadm: /dev/dm-4 has wrong uuid.
>> mdadm: no RAID superblock on /dev/dm-3
>> mdadm: /dev/dm-3 has wrong uuid.
>> mdadm: cannot open device /dev/dm-2: Device or resource busy
>> mdadm: /dev/dm-2 has wrong uuid.
>> mdadm: no RAID superblock on /dev/dm-1
>> mdadm: /dev/dm-1 has wrong uuid.
>> mdadm: no RAID superblock on /dev/dm-0
>> mdadm: /dev/dm-0 has wrong uuid.
>> mdadm: no RAID superblock on /dev/sde
>> mdadm: /dev/sde has wrong uuid.
>> mdadm: no RAID superblock on /dev/sdd
>> mdadm: /dev/sdd has wrong uuid.
>> mdadm: cannot open device /dev/sdc7: Device or resource busy
>> mdadm: /dev/sdc7 has wrong uuid.
>> mdadm: cannot open device /dev/sdc6: Device or resource busy
>> mdadm: /dev/sdc6 has wrong uuid.
>> mdadm: cannot open device /dev/sdc5: Device or resource busy
>> mdadm: /dev/sdc5 has wrong uuid.
>> mdadm: no RAID superblock on /dev/sdc2
>> mdadm: /dev/sdc2 has wrong uuid.
>> mdadm: cannot open device /dev/sdc1: Device or resource busy
>> mdadm: /dev/sdc1 has wrong uuid.
>> mdadm: cannot open device /dev/sdc: Device or resource busy
>> mdadm: /dev/sdc has wrong uuid.
>> mdadm: no RAID superblock on /dev/sda
>> mdadm: /dev/sda has wrong uuid.
>> mdadm: no RAID superblock on /dev/sdb
>> mdadm: /dev/sdb has wrong uuid.
>> mdadm: /dev/sdd1 is identified as a member of /dev/md/0, slot 2.
>> mdadm: /dev/sda1 is identified as a member of /dev/md/0, slot 0.
>> mdadm: /dev/sdb1 is identified as a member of /dev/md/0, slot 1.
>> mdadm: added /dev/sdb1 to /dev/md/0 as 1
>> mdadm: added /dev/sdd1 to /dev/md/0 as 2
>> mdadm: added /dev/sda1 to /dev/md/0 as 0
>> mdadm: /dev/md/0 has been started with 2 drives (out of 3).
>>
>> ---
>>
>> mdadm --examine /dev/sd{a,b,d}1
>>
>> /dev/sda1:
>> Magic : a92b4efc
>> Version : 1.2
>> Feature Map : 0x0
>> Array UUID : 7d8a7c68:95a230d0:0a8f6e74:4c8f81e9
>> Name : XEN-HOST:0 (local to host XEN-HOST)
>> Creation Time : Mon Dec 20 09:48:07 2010
>> Raid Level : raid5
>> Raid Devices : 3
>>
>> Avail Dev Size : 1953517954 (931.51 GiB 1000.20 GB)
>> Array Size : 3907035136 (1863.02 GiB 2000.40 GB)
>> Used Dev Size : 1953517568 (931.51 GiB 1000.20 GB)
>> Data Offset : 2048 sectors
>> Super Offset : 8 sectors
>> State : clean
>> Device UUID : 25f4baf0:9a378d2c:16a87f0c:ff89b2c8
>>
>> Update Time : Mon Feb 28 23:35:20 2011
>> Checksum : 3745d2b9 - correct
>> Events : 33374
>>
>> Layout : left-symmetric
>> Chunk Size : 512K
>>
>> Device Role : Active device 0
>> Array State : AAA ('A' == active, '.' == missing)
>>
>> /dev/sdb1:
>> Magic : a92b4efc
>> Version : 1.2
>> Feature Map : 0x0
>> Array UUID : 7d8a7c68:95a230d0:0a8f6e74:4c8f81e9
>> Name : XEN-HOST:0 (local to host XEN-HOST)
>> Creation Time : Mon Dec 20 09:48:07 2010
>> Raid Level : raid5
>> Raid Devices : 3
>>
>> Avail Dev Size : 1953517954 (931.51 GiB 1000.20 GB)
>> Array Size : 3907035136 (1863.02 GiB 2000.40 GB)
>> Used Dev Size : 1953517568 (931.51 GiB 1000.20 GB)
>> Data Offset : 2048 sectors
>> Super Offset : 8 sectors
>> State : clean
>> Device UUID : f20ab5fd:1f141cae:e0547278:d6cf063e
>>
>> Update Time : Mon Feb 28 23:35:20 2011
>> Checksum : a715b8ad - correct
>> Events : 33374
>>
>> Layout : left-symmetric
>> Chunk Size : 512K
>>
>> Device Role : Active device 1
>> Array State : AAA ('A' == active, '.' == missing)
>>
>> /dev/sdd1:
>> Magic : a92b4efc
>> Version : 1.2
>> Feature Map : 0x0
>> Array UUID : 7d8a7c68:95a230d0:0a8f6e74:4c8f81e9
>> Name : XEN-HOST:0 (local to host XEN-HOST)
>> Creation Time : Mon Dec 20 09:48:07 2010
>> Raid Level : raid5
>> Raid Devices : 3
>>
>> Avail Dev Size : 1953521072 (931.51 GiB 1000.20 GB)
>> Array Size : 3907035136 (1863.02 GiB 2000.40 GB)
>> Used Dev Size : 1953517568 (931.51 GiB 1000.20 GB)
>> Data Offset : 2048 sectors
>> Super Offset : 8 sectors
>> State : clean
>> Device UUID : 33d70114:ffdc4fcc:2c8d65ba:ab50bab2
>>
>> Update Time : Mon Feb 28 23:29:05 2011
>> Checksum : 923d11a2 - correct
>> Events : 33368
>>
>> Layout : left-symmetric
>> Chunk Size : 512K
>>
>> Device Role : Active device 2
>> Array State : AAA ('A' == active, '.' == missing)
>>
>> ---
>>
>>
>> Any ideas or tips? I am considering this might be a bug, but I have only
>> had this problem in my Debian Squeeze system.
>>
>
> What do cat /proc/mdstat and mdadm -D /dev/md0 show you? Also have you
> updated your mdadm.conf (and the mdadm.conf in the initramfs if you use
> one)?
>
After a reboot I see
cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sda1[0] sdb1[1]
1953517568 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/2] [UU_]
unused devices:
But sometimes I see
cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active (auto-read-only) raid5 sda1[0] sdb1[1]
1953517568 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/2] [UU_]
unused devices:
QUESTION: What does '(auto-read-only)' mean?
In either case --detail output is the same for both cases.
mdadm -D /dev/md0
/dev/md0:
Version : 1.2
Creation Time : Mon Dec 20 09:48:07 2010
Raid Level : raid5
Array Size : 1953517568 (1863.02 GiB 2000.40 GB)
Used Dev Size : 976758784 (931.51 GiB 1000.20 GB)
Raid Devices : 3
Total Devices : 2
Persistence : Superblock is persistent
Update Time : Tue Mar 1 13:50:53 2011
State : clean, degraded
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 512K
Name : XEN-HOST:0 (local to host XEN-HOST)
UUID : 7d8a7c68:95a230d0:0a8f6e74:4c8f81e9
Events : 33422
Number Major Minor RaidDevice State
0 8 1 0 active sync /dev/sda1
1 8 17 1 active sync /dev/sdb1
2 0 0 2 removed
Hmm, so the array is aware that it is missing drive number/RaidDevice of 2, I am not sure what implication of having a major/minor of 0.
QUESTION: Must the Major/Minor information exactly match what the system detect vs the meta data on the array (I presume)?
If that is the case it looks like I need to make drive number/RaidDevice 2 have a major/minor 8/49.
ls -l /dev/sda1
brw-rw---- 1 root disk 8, 1 Mar 1 14:17 /dev/sda1
ls -l /dev/sdb1
brw-rw---- 1 root disk 8, 17 Mar 1 14:17 /dev/sdb1
ls -l /dev/sdd1
brw-rw---- 1 root floppy 8, 49 Mar 1 14:17 /dev/sdd1
Until I find a solution I am manually running:
mdadm --re-add /dev/md0 /dev/sdd1 -vvv
mdadm: re-added /dev/sdd1
or
mdadm --add /dev/md0 /dev/sdd1 -vvv
mdadm: re-added /dev/sdd1
Which then gives me:
cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sdd1[3] sda1[0] sdb1[1]
1953517568 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/2] [UU_]
[>....................] recovery = 0.1% (1222156/976758784) finish=622.3min speed=26126K/sec
unused devices:
QUESTION: Here is seems sdd1 is given drive number 3 not 2, is that a problem? (e.g: sdd1[2] vs sdd1[3])
I am also certain my mdadm.conf on my file system is in sync/updated with the one in my initramfs for all kernels actually.
cat /etc/mdadm/mdadm.conf
# mdadm.conf
#
# Please refer to mdadm.conf(5) for information about this file.
#
# by default, scan all partitions (/proc/partitions) for MD superblocks.
# alternatively, specify devices to scan, using wildcards if desired.
DEVICE partitions containers
# auto-create devices with Debian standard permissions
CREATE owner=root group=disk mode=0660 auto=yes
# automatically tag new arrays as belonging to the local system
HOMEHOST
# definitions of existing MD arrays
ARRAY /dev/md/0 metadata=1.2 UUID=7d8a7c68:95a230d0:0a8f6e74:4c8f81e9 name=XEN-HOST:0
In trying to fix the problem I attempted to change the preferred minor of an MD array (RAID) by follow these instructions.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# you need to manually assemble the array to change the preferred minor
# if you manually assemble, the superblock will be updated to reflect
# the preferred minor as you indicate with the assembly.
# for example, to set the preferred minor to 4:
mdadm --assemble /dev/md4 /dev/sd[abc]1
# this only works on 2.6 kernels, and only for RAID levels of 1 and above.
mdadm --assemble /dev/md0 /dev/sd{a,b,d}1 -vvv
mdadm: looking for devices for /dev/md0
mdadm: /dev/sda1 is identified as a member of /dev/md0, slot 0.
mdadm: /dev/sdb1 is identified as a member of /dev/md0, slot 1.
mdadm: /dev/sdd1 is identified as a member of /dev/md0, slot 2.
mdadm: added /dev/sdb1 to /dev/md0 as 1
mdadm: added /dev/sdd1 to /dev/md0 as 2
mdadm: added /dev/sda1 to /dev/md0 as 0
mdadm: /dev/md0 has been started with 2 drives (out of 3) and 1 rebuilding.
So because I specified all the drives, I assume this is the same things as assembling the RAID degraded and then manually re-adding the last one (/dev/sdd1).
-M
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