Hi all, I just installed the new stable Squeeze system, and moved over a
raid5 from an older system. For some reason, it now wants to mount as md127
instead of md0. I've been unable to map it back to md0.
Below is all the terminal commands I thought of as relevant, along with my
commentary. I'm downright befuddled, and would love any ideas or
suggestions.
Looking at mdstat shows it happily living as md127:
> root@jupiter:~# cat /proc/mdstat
> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5]
> [raid4] [raid10]
> md127 : active (auto-read-only) raid5 sde1[0] sdb1[3] sdd1[2] sdc1[1]
> 4395407808 blocks level 5, 64k chunk, algorithm 2 [4/4] [UUUU]
>
> unused devices: <none>
Here's mdadm's output about md127:
> root@jupiter:~# mdadm -D /dev/md127
/dev/md127:
Version : 0.90
Creation Time : Fri Oct 30 15:00:52 2009
Raid Level : raid5
Array Size : 4395407808 (4191.79 GiB 4500.90 GB)
Used Dev Size : 1465135936 (1397.26 GiB 1500.30 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 127
Persistence : Superblock is persistent
> Update Time : Thu Feb 17 14:07:02 2011
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
> Layout : left-symmetric
Chunk Size : 64K
> UUID : df6df64f:7f3a3af9:e34ba98b:5bc5bc0e
Events : 0.1030180
> Number Major Minor RaidDevice State
0 8 65 0 active sync /dev/sde1
1 8 33 1 active sync /dev/sdc1
2 8 49 2 active sync /dev/sdd1
3 8 17 3 active sync /dev/sdb1
However, there's lingering references to md0:
> root@jupiter:~# mdadm -Ds
> ARRAY /dev/md/0_0 metadata=0.90 UUID=df6df64f:7f3a3af9:e34ba98b:5bc5bc0e
The devices themselves have a preferred minor of md0:
> root@jupiter:~# mdadm --examine /dev/sdb1
/dev/sdb1:
Magic : a92b4efc
Version : 0.90.00
UUID : df6df64f:7f3a3af9:e34ba98b:5bc5bc0e
Creation Time : Fri Oct 30 15:00:52 2009
Raid Level : raid5
Used Dev Size : 1465135936 (1397.26 GiB 1500.30 GB)
Array Size : 4395407808 (4191.79 GiB 4500.90 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 0
> Update Time : Thu Feb 17 14:07:02 2011
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Checksum : 36a288b2 - correct
Events : 1030180
> Layout : left-symmetric
Chunk Size : 64K
> Number Major Minor RaidDevice State
this 3 8 1 3 active sync /dev/sda1
> 0 0 8 49 0 active sync /dev/sdd1
1 1 8 17 1 active sync /dev/sdb1
2 2 8 33 2 active sync /dev/sdc1
3 3 8 1 3 active sync /dev/sda1
The output for each device is similar... and in each device, it thinks of
itself as a prior device. sdb1 says "this" is sda1, sdc1 says "this" is
sdb1, sdd1 says "this" is sdc1, and sde1 says "this" is sdd1. I don't know
if this is important, but I definitely think it's worth pointing out.
I've also tried stopping the device and reassembling as md0:
> root@jupiter:~# cat /proc/mdstat
> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5]
> [raid4] [raid10]
> md127 : active (auto-read-only) raid5 sde1[0] sdb1[3] sdd1[2] sdc1[1]
> 4395407808 blocks level 5, 64k chunk, algorithm 2 [4/4] [UUUU]
>
> unused devices: <none>
> root@jupiter:~# mdadm --stop /dev/md127
> mdadm: stopped /dev/md127
> root@jupiter:~# mdadm --assemble /dev/md0 /dev/sdb1 /dev/sdc1 /dev/sdd1
> /dev/sde1
> mdadm: /dev/md0 has been started with 4 drives.
> root@jupiter:~# cat /proc/mdstat
> Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5]
> [raid4] [raid10]
> md0 : active (auto-read-only) raid5 sde1[0] sdb1[3] sdd1[2] sdc1[1]
> 4395407808 blocks level 5, 64k chunk, algorithm 2 [4/4] [UUUU]
>
> unused devices: <none>
This works fine, until reboot, at which point we're back to md127. In
/var/log/syslog, I find this little oddity:
> Feb 17 15:33:35 jupiter mdadm[1580]: DeviceDisappeared event detected on md
> device /dev/md0
> Feb 17 15:33:35 jupiter mdadm[1580]: NewArray event detected on md device
> /dev/md127
The whole thing has me pretty stumped, what am I missing?
