PLEASE HELP!!! RAID problems with 10.04

Maxime Alarie malarie at
Mon Apr 12 17:26:21 UTC 2010

What does /proc/mdstat says?  Please print the  output.

Maxime Alarie 
Spécialiste IT / IT Specialist
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-----Original Message-----
From: ubuntu-users-bounces at [mailto:ubuntu-users-bounces at] On Behalf Of Alvin Thompson
Sent: Monday, April 12, 2010 12:11 PM
To: ubuntu-users at
Subject: PLEASE HELP!!! RAID problems with 10.04

Sorry about the repost, but can anyone please help me with this?  I really need the data on this drive.  I'm pretty sure the install altered the partition where the RAID drive resides, but I don't know how to fix it.  Can anyone please help?

I tried installing 10.04 server on a system and now my RAID5 data device is corrupted.  I did not tell the installer to do anything to my RAID device when I was installing, but I did tell the installer to create other RAID5 devices from other partitions on the same drives.  I have a lot of very important data on that device so any suggestions would be appreciated.  Can anyone please help, or does anyone have any idea on how to fix?

First, this was my original setup.  I had 4 500GB drives (sda-sdd), each with identical partition tables:
 sd[abcd]1:  25GB
 sd[abcd]2: 475GB    RAID5

My RAID5 device was /dev/md1 and consisted of partition 2 on all drives (4 active, no spares):
 md1 = sd[abcd]2    1.2TB    formatted as XFS

My previous linux install was on sda1 (25GB, no RAID).  The remaining partitions (sd[bcd]1) were unused in my old setup.

Everything was working fine before I attempted to install Ubuntu.

I decided to do a clean install of 10.04 to take advantage of grub2 booting straight to a RAID5 partition.  I specified manual partitioning, removed partition 1 on all drives (leaving partition 2 alone), and set up partitions/RAID as follows:
 --added partitions and RAID devices--
 sd[abcd]1:  22GB    RAID5    md2    /
 sd[abcd]3:   3GB    RAID5    md3    (swap)
 --original, untouched RAID device--
 sd[abcd]2: 475GB    RAID5    md1    (not mounted)

I did not touch md1 or partition 2 on any drive (my original RAID device), but when I chose to write changes to disk, the installer listed partition 2 as one of the partitions to be modified on the drives.  I did NOT want partition 2 to be modified so I backed out of all changes and redid them, making doubly sure that I did not modify partition 2 or md1.  The partitioner still listed partition 2 as one of the partitions to be modified, and this time I agreed, assuming since I hadn't actually changed anything there would be no problems (my mistake).

Now that the install is complete, as you can guess, md1 is not working, but md2 and md3 (created during the install) are.  I'm assuming the layout for partition 2 was indeed modified, so how do I fix it?  The way I see it, there are 2 very serious bugs here:

1. The installer modified partitions without the user expressly telling it to do so.
2. The installer modified partitions that were already used by a RAID device.  Partitions should NEVER EVER be modified until any raid devices that use them are removed, even if the installer did not create the RAID device.

Can anyone please help?


some possibly relevant output:

alvin at io:~$ sudo mount -t xfs /dev/md1 /data/
mount: wrong fs type, bad option, bad superblock on /dev/md1,
      missing codepage or helper program, or other error
      In some cases useful info is found in syslog - try
      dmesg | tail  or so

alvin at io:~$ sudo xfs_check /dev/md1
xfs_check: /dev/md1 is not a valid XFS filesystem (unexpected SB magic number 0x00000000)
xfs_check: WARNING - filesystem uses v1 dirs,limited functionality provided.
xfs_check: read failed: Invalid argument
xfs_check: data size check failed
cache_node_purge: refcount was 1, not zero (node=0x1eba990)
xfs_check: cannot read root inode (22)
bad superblock magic number 0, giving up

alvin at io:~$ sudo cat /proc/mdstat 
Personalities : [raid6] [raid5] [raid4] [linear] [multipath] [raid0] [raid1] [raid10] 
md1 : active raid5 sdc2[2] sda2[0] sdd2[3] sdb2[1]
     1391919552 blocks level 5, 64k chunk, algorithm 2 [4/4] [UUUU]

md3 : active raid5 sdd3[3] sdc3[2] sda3[0] sdb3[1]
     8776512 blocks level 5, 64k chunk, algorithm 2 [4/4] [UUUU]

md2 : active raid5 sdd1[3] sda1[0] sdc1[2] sdb1[1]
     64450368 blocks level 5, 64k chunk, algorithm 2 [4/4] [UUUU]

unused devices: <none>

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