Hi,

Recently had an issue with my RAID1 array. I updated to Ubunt 9.blahhh and this left one of my disks not working.

From memory I found I now had a /dev/md/0 where before I had a /dev/md0.

Managed to mount one of the drives I think by doing mount /dev/md/0 and this gave me access to my drive and I thought that this was just a changed in how the mdadm stuff works.

Current state is

root@denise:~# cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid1 sdc1[1]
488383936 blocks [2/1] [_U]

md_d0 : active raid1 sdd1[0]
488383936 blocks [2/1] [U_]

And I have the following devices

root@denise:~# ls -lR /dev/md*
brw-rw---- 1 root disk 9, 0 2010-01-05 19:38 /dev/md0
brw-rw---- 1 root disk 253, 0 2010-01-05 19:18 /dev/md_d0
lrwxrwxrwx 1 root root 7 2010-01-05 19:18 /dev/md_d0p1 -> md/d0p1
lrwxrwxrwx 1 root root 7 2010-01-05 19:18 /dev/md_d0p2 -> md/d0p2
lrwxrwxrwx 1 root root 7 2010-01-05 19:18 /dev/md_d0p3 -> md/d0p3
lrwxrwxrwx 1 root root 7 2010-01-05 19:18 /dev/md_d0p4 -> md/d0p4

/dev/md:
total 0
brw-rw---- 1 root disk 9, 0 2010-01-05 19:38 0
brw------- 1 root root 253, 0 2010-01-05 19:18 d0
brw------- 1 root root 253, 1 2010-01-05 19:18 d0p1
brw------- 1 root root 253, 2 2010-01-05 19:18 d0p2
brw------- 1 root root 253, 3 2010-01-05 19:18 d0p3
brw------- 1 root root 253, 4 2010-01-05 19:18 d0p4

A drive is mounted on from /dev/md/0 and does show the data. However I have a message that says

DegradedArray event on /dev/md0:denise.xxx.xx

I also noticed that it swaps between sdd1 and sdc1. I suspect this is me mount the drive from the wrong place.

Other detail which may be useful.

root@denise:~# mdadm --detail /dev/md/0
/dev/md/0:
Version : 00.90
Creation Time : Wed Jan 21 18:45:58 2009
Raid Level : raid1
Array Size : 488383936 (465.76 GiB 500.11 GB)
Used Dev Size : 488383936 (465.76 GiB 500.11 GB)
Raid Devices : 2
Total Devices : 1
Preferred Minor : 0
Persistence : Superblock is persistent

Update Time : Wed Jan 6 14:25:42 2010
State : clean, degraded
Active Devices : 1
Working Devices : 1
Failed Devices : 0
Spare Devices : 0

UUID : 5c3f9459:b5ba36d7:ecb97297:886d2585 (local to host denise.bibble.co.nz)
Events : 0.2424

Number Major Minor RaidDevice State
0 0 0 0 removed
1 8 33 1 active sync /dev/sdc1

My current approach is to copy it all off and then build the RAID however I would like to try and understand how I could recover from this.

Regards,
Iain

What is in your /etc/mdadm/mdadm.conf ?
What does running sudo /usr/share/mdadm/mkconf say?
You are showing that you have 2 arrays: md0 and md_d0, is that correct?
What devices are supposed to be in the array? sda1, sdb1, ect...

The configuration is empty.


# 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

# This file was auto-generated on Wed, 21 Jan 2009 16:39:36 +1300
# by mkconf $Id$

And it is supposed to be sdc1 and sdd1

It shouldn't be that way. Is there anything else in /etc/mdadm/ ?
does sudo /usr/share/mdadm/mkconf output what appears to be correct?

If so, you can create a new /etc/mdadm/mdadm.conf with:
sudo /usr/share/mdadm/mkconf > /etc/mdadm/mdadm.conf

The man pages have a good overview of how all of this stuff works:
http://linux.die.net/man/8/mdadm
http://www.howtoforge.com/how-to-set...n-debian-lenny