Software RAID Degraded

[SuperMe79]

I have installed ubuntu 8.10 server. I configured software raid with 3 raid1 devices



sda1 + sdb1 = md0 swap
sda2 + sdb2 = md1 ext3 /
sda3 + sdb3 = md2 ext3 /data


I have booted the server and discovered that the software raid is not working



# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md2 : active raid1 dm-2[0]
163083776 blocks [2/1] [U_]

md1 : active raid1 dm-3[0]
78123968 blocks [2/1] [U_]

md0 : active raid1 dm-1[0]
3903680 blocks [2/1] [U_]

unused devices: <none>


mdadm reports a degraded array. All three raid arrays report the same.



# mdadm -D /dev/md0
/dev/md0:
Version : 00.90
Creation Time : Sat Mar 28 20:45:44 2009
Raid Level : raid1
Array Size : 3903680 (3.72 GiB 4.00 GB)
Used Dev Size : 3903680 (3.72 GiB 4.00 GB)
Raid Devices : 2
Total Devices : 1
Preferred Minor : 0
Persistence : Superblock is persistent

Update Time : Sat Mar 28 21:19:09 2009
State : clean, degraded
Active Devices : 1
Working Devices : 1
Failed Devices : 0
Spare Devices : 0

UUID : e0514f53:06fa9306:fa1c93f5:ba501f28
Events : 0.14

Number Major Minor RaidDevice State
0 254 1 0 active sync /dev/block/254:1
1 0 0 1 removed




# mdadm --examine /dev/sda1
/dev/sda1:
Magic : a92b4efc
Version : 00.90.00
UUID : e0514f53:06fa9306:fa1c93f5:ba501f28
Creation Time : Sat Mar 28 20:45:44 2009
Raid Level : raid1
Used Dev Size : 3903680 (3.72 GiB 4.00 GB)
Array Size : 3903680 (3.72 GiB 4.00 GB)
Raid Devices : 2
Total Devices : 1
Preferred Minor : 0

Update Time : Sat Mar 28 21:27:01 2009
State : clean
Active Devices : 1
Working Devices : 1
Failed Devices : 1
Spare Devices : 0
Checksum : d8bc9a6d - correct
Events : 18


Number Major Minor RaidDevice State
this 0 254 1 0 active sync /dev/block/254:1

0 0 254 1 0 active sync /dev/block/254:1
1 1 0 0 1 faulty removed




# mdadm --examine /dev/sdb1
/dev/sdb1:
Magic : a92b4efc
Version : 00.90.00
UUID : e0514f53:06fa9306:fa1c93f5:ba501f28
Creation Time : Sat Mar 28 20:45:44 2009
Raid Level : raid1
Used Dev Size : 3903680 (3.72 GiB 4.00 GB)
Array Size : 3903680 (3.72 GiB 4.00 GB)
Raid Devices : 2
Total Devices : 1
Preferred Minor : 0

Update Time : Sat Mar 28 21:27:01 2009
State : clean
Active Devices : 1
Working Devices : 1
Failed Devices : 1
Spare Devices : 0
Checksum : d8bc9a6d - correct
Events : 18


Number Major Minor RaidDevice State
this 0 254 1 0 active sync /dev/block/254:1

0 0 254 1 0 active sync /dev/block/254:1
1 1 0 0 1 faulty removed




# 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

# 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 <system>

# instruct the monitoring daemon where to send mail alerts
MAILADDR root

# definitions of existing MD arrays
ARRAY /dev/md0 level=raid1 num-devices=2 UUID=e0514f53:06fa9306:fa1c93f5:ba501f28
ARRAY /dev/md1 level=raid1 num-devices=2 UUID=1168b618:0b03c90a:0531a492:831787b1
ARRAY /dev/md2 level=raid1 num-devices=2 UUID=59828836:a271882f:72976378:e41c5711

# This file was auto-generated on Sat, 28 Mar 2009 20:51:49 +0000
# by mkconf $Id$


This is what I have tried to resolve this problem


Disabling / enabling the fakeraid support on my motherboard
Editing /etc/mdadm/mdadm.conf and specifying that only /dev/sd[ab]* should be checked
Using mdadm /dev/md0 -r /dev/sd[ab]1 and corresponding add command to remove / add the discs from the array


None of this has worked. My array is still reported as degraded. Any ideas would be greatly appreciated.

This post may be of similar ilk

http://ubuntuforums.org/showthread.php?t=917675&highlight=degraded+software+raid

[combatwombat_nz]

Try replacing your SATA cabling. Dodgy/cheap cables cause stupid errors like missing drives.

[SuperMe79]

Thanks for the suggestion. Unfortunately this isn't the problem in my case. The hardware including cables are fine. I know this because before I installed ubuntu the hardware was running a gentoo server with software raid configured and working fine. The ubuntu kernel is newer than the gentoo kernel. I installed the gentoo system about 3 years ago using the kernel that was current at that time.

[SuperMe79]

Unfortunately I still haven't been able to resolve this problem. Please help.

[SuperMe79]

Seems like no-one is going to help me with this issue. Very disappointing.

[ronparent]

Have you tried posting to the Server Platforms forum? The people who populate that forum may be more knowledgable of mdadm protocols and associated problems. Although I myself have configured both raid0 and raid1 systems I never progress past dmraid to get them reconized in my ubuntu installs. Someone more knowledgeble might be able to make more sense of you original posting.

[SuperMe79]

Problem solved. I abandoned Ubuntu and installed Gentoo instead.

[ziegi]

I just faced the same problem!
The solution is to uninstall the dmraid package
just using mdadm works fine