mdadm assembled the other superblock thus failing to boot
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| mdadm (Ubuntu) |
Confirmed
|
Low
|
Unassigned | ||
Bug Description
I just upgraded a working 10.04 LTS server to 12.04 LTS. The server has two non-boot drives in a software RAID1 configuration. This array worked fine in 10.04 LTS.
When the machine boots I should get one active array, /dev/md0 consisting of /dev/sdb1 and /dev/sdc1. Instead, I get dumped to a busybox session and after quitting that and booting I get two inactive arrays: md0 (consisting of /dev/sdc1 as spare) and md127 (consisting of /dev/sdb as spare). If I run mdadm --detail /dev/md0 or mdadm --detail /dev/md127 I get that the device does not appear to be active.
Once I've finished booting, I can assemble my array manually by running mdadm --stop /dev/md0 and mdadm --stop /dev/md127 and then assembling the array with mdadm --assemble /dev/md0 /dev/sdb1 /dev/sdc1.
Below are the results of some troubleshooting:
$ lsb_release -rd
Description: Ubuntu 12.04.2 LTS
Release: 12.04
$ apt-cache policy mdadm
mdadm:
Installed: 3.2.5-1ubuntu0.2
Candidate: 3.2.5-1ubuntu0.2
Version table:
*** 3.2.5-1ubuntu0.2 0
500 http://
100 /var/lib/
3.2.3-2ubuntu1 0
500 http://
$ cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : inactive sdc1[1](S)
1953513408 blocks
md127 : inactive sdb[2](S)
1953514496 blocks
unused devices: <none>
$ mdadm --examine /dev/sdb1
/dev/sdb1:
Magic : a92b4efc
Version : 0.90.00
UUID : a4176cee:
Creation Time : Thu Jul 7 09:32:01 2011
Raid Level : raid1
Used Dev Size : 1953513408 (1863.02 GiB 2000.40 GB)
Array Size : 1953513408 (1863.02 GiB 2000.40 GB)
Raid Devices : 2
Total Devices : 2
Preferred Minor : 0
Update Time : Wed Apr 3 10:32:36 2013
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Checksum : d685ab7e - correct
Events : 722
Number Major Minor RaidDevice State
this 0 8 17 0 active sync /dev/sdb1
0 0 8 17 0 active sync /dev/sdb1
1 1 8 33 1 active sync /dev/sdc1
$ mdadm --examine /dev/sdc1
/dev/sdc1:
Magic : a92b4efc
Version : 0.90.00
UUID : a4176cee:
Creation Time : Thu Jul 7 09:32:01 2011
Raid Level : raid1
Used Dev Size : 1953513408 (1863.02 GiB 2000.40 GB)
Array Size : 1953513408 (1863.02 GiB 2000.40 GB)
Raid Devices : 2
Total Devices : 2
Preferred Minor : 0
Update Time : Wed Apr 3 10:32:36 2013
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Checksum : d685ab90 - correct
Events : 722
Number Major Minor RaidDevice State
this 1 8 33 1 active sync /dev/sdc1
0 0 8 17 0 active sync /dev/sdb1
1 1 8 33 1 active sync /dev/sdc1
| Austin (ninjamonic) wrote | #1 |
| Austin (ninjamonic) wrote | #2 |
| Dimitri John Ledkov (xnox) wrote | #3 |
| summary: |
- mdadm devices not recognized correctly at boot + mdadm assembled the other superblock thus failing to boot |
| Changed in mdadm (Ubuntu): | |
| status: | New → Confirmed |
| importance: | Undecided → Low |
I'm digging into this some more and it seems that mdadm in Ubuntu 12.04 is detecting an old unused superblock on /dev/sdb that mdadm in Ubuntu 10.04 ignored.
$ mdadm --examine --scan --verbose
ARRAY /dev/md1 level=raid1 num-devices=2 UUID=5fb6928e:
spares=1 devices=/dev/sdb
ARRAY /dev/md0 level=raid1 num-devices=2 UUID=a4176cee:
devices=
When we examine /dev/sdb, we see there's an old superblock there (note the update date is Thu Jul 7 09:00:21 2011).
$ mdadm --examine /dev/sdb
/dev/sdb:
Magic : a92b4efc
Version : 0.90.00
UUID : 5fb6928e:
Creation Time : Fri Jul 1 10:00:58 2011
Raid Level : raid1
Used Dev Size : 1953513408 (1863.02 GiB 2000.40 GB)
Array Size : 1953513408 (1863.02 GiB 2000.40 GB)
Raid Devices : 2
Total Devices : 2
Preferred Minor : 1
Update Time : Thu Jul 7 09:00:21 2011
State : clean
Active Devices : 1
Working Devices : 2
Failed Devices : 1
Spare Devices : 1
Checksum : 57d747d3 - correct
Events : 24
Number Major Minor RaidDevice State
this 2 8 16 2 spare /dev/sdb
0 0 8 33 0 active sync /dev/sdc1
1 1 0 0 1 faulty removed
2 2 8 16 2 spare /dev/sdb