Ubuntu
mdadm package

Created /dev/md0 on Ubuntu, can't mount on Kubuntu instal

Asked by Paul Barron

RAID 0 Mounts under one linux but not under another.

I have a system with 5 x 500 GB SATA disks
one of the disks (/dev/sde) is a triple boot system disk with Ubuntu, Kubuntu and Windows XP installed in thier own partitions.
The other four disks form a RAID 0 that I hope I will be able to use for editing High definition Video.
I want to be able to boot into Ubuntu or Kubuntu and acess the RAID.

I used mdadm to create the RAID on ubu (/dev/md0)
During the process of creating the RAID I formatted each disk (/dev/sda,/dev/sdb,/dev/sdc,/dev/sdd with jfs using gparted, changed the flags to raid, then when the RAID had been created I created a jfs file system on the RAID.
I used jfs as the file system as a high throughput is required.
The RAID would not mount on Ubuntu untill I created the /etc/mdadm.mdadm.conf file
according to.

http://bfish.xaedalus.net/?p=188
"sudo echo "DEVICE partitions" > /etc/mdadm/mdadm.conf
sudo mdadm --detail --scan >> /etc/mdadm/mdadm.conf"

The RAID mounts on ubuntu where it was created but I just can't seem to find information on mounting it on Kubuntu after rebooting

trying sudo fsck -n /dev/md0 on Kubuntu I get
paulb@PostSFX:~$ sudo fsck -n /dev/md0
fsck 1.40.8 (13-Mar-2008)
fsck.jfs version 1.1.11, 05-Jun-2006
processing started: 9/24/2008 17.55.26
The current device is: /dev/md0

The superblock does not describe a correct jfs file system.

If device /dev/md0 is valid and contains a jfs file system,
then both the primary and secondary superblocks are corrupt
and cannot be repaired, and fsck cannot continue.

Otherwise, make sure the entered device /dev/md0 is correct.

on ubuntu where the RAID Mounts and seems to work perfectly.
/dev/md0 unmounted
paulb@PostSFX:~$ sudo fsck -n /dev/md0
fsck 1.40.8 (13-Mar-2008)
fsck.jfs version 1.1.11, 05-Jun-2006
processing started: 9/24/2008 18.23.19
The current device is: /dev/md0
Block size in bytes: 4096
Filesystem size in blocks: 488383936
**Phase 1 - Check Blocks, Files/Directories, and Directory Entries
**Phase 2 - Count links
**Phase 3 - Duplicate Block Rescan and Directory Connectedness
**Phase 4 - Report Problems
**Phase 5 - Check Connectivity
**Phase 6 - Perform Approved Corrections
**Phase 7 - Verify File/Directory Allocation Maps
**Phase 8 - Verify Disk Allocation Maps
1953535744 kilobytes total disk space.
        0 kilobytes in 1 directories.
   251403 kilobytes in 30 user files.
        0 kilobytes in extended attributes
   331425 kilobytes reserved for system use.
1952952916 kilobytes are available for use.
File system checked READ ONLY.
Filesystem is clean.

I have jfs installed on Ubuntu and Kubuntu

Any help would be greatly appreciated.

Paul

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Paul Barron (paul-barron) said : 		#1

I tried to set up the same array with xfs and had the same problem.
 Trying the commands mdadm --detail /dev/md0 on Kubuntu, the table at the end showed active sync /dev/sda instead of active sync /dev/sda, so was not showing the partition. After examining the devices /dev/sda,b,c,d with GParted in Ubuntu 8.04 I found that a and b had a partition but no file system and c and d had an xfs file system.
on using mdadm --examine /dev/sda and mdadm --examine /dev/sda1 I noticed the device had a different UUID than the partition. I decided things were in a bit of a mess, stopped and removed the raid zeroed the superblocks for each of the four drives and followed instructions at http://www.mythtv.org/wiki/index.php/RAID#RAID.
After creating the /etc/madm/madm.conf file I coppied it to Kubuntu.
On switching to rebooting to Kubuntu, the array had mounted. :-)
appologies to anyone who has read and tried to figure it all out the above.
Now I just need to get the ATI drivers for HD4850 and then a spot of digital content creation.