Corrupted RAID 50 (aparently?) array. Help needed.

Hi list,

Hope someone can give me the right direction on how to resolve this.

I have 12 hard drives with RAID software. (250 GB each disk) I just  
know it was a 2 TB array. The old operating system which supported the  
array is no longer online. (just in case someone asks me to check the  
mdadm.conf file)

 From what I can see with mdadm,is that there are 2 x RAID5 arrays of  
990.72 GB each. (2 TB the whole array). So I believed that there is a  
RAID0 between both RAID5 arrays. Right? (RAID50) The first RAID5 group  
is composed by 5 discs, all of them active. Here is the post: (all  
/dev/sdb4 /dev/sdc4 /dev/sdd4 /dev/sde4 /dev/sdf4 are similar and have  
the same UUID)

# mdadm --examine /dev/sdb4

----------------------------
/dev/sdb4:
           Magic : a92b4efc
         Version : 00.91.00
            UUID : 48b86fc7:adbd7bbe:df7c7359:36df38af
   Creation Time : Tue Apr 24 18:14:28 2007
      Raid Level : raid5
   Used Dev Size : 241873792 (230.67 GiB 247.68 GB)
      Array Size : 967495168 (922.68 GiB 990.72 GB)
    Raid Devices : 5
   Total Devices : 5
Preferred Minor : 0

   Reshape pos'n : 0
       New Level : raid0
      New Layout : left-asymmetric
   New Chunksize : 0

     Update Time : Mon Nov 29 21:01:33 1999
           State : clean
  Active Devices : 5
Working Devices : 5
  Failed Devices : 0
   Spare Devices : 0
        Checksum : 42da3120 - correct
          Events : 0.61

          Layout : left-symmetric
      Chunk Size : 64K

       Number   Major   Minor   RaidDevice State
this     0       3        4        0      active sync

    0     0       3        4        0      active sync
    1     1      22        4        1      active sync
    2     2      33        4        2      active sync
    3     3      34        4        3      active sync
    4     4      56        4        4      active sync
---------------------

But If I try to assemble this 1st RAID5 array:

# mdadm --assemble /dev/md0 /dev/sdb4 /dev/sdc4 /dev/sdd4 /dev/sde4 /dev/sdf4
mdadm: Failed to restore critical section for reshape, sorry.

Is not possible. I also try the build option:

# mdadm --build /dev/md0 -l5 -n5 --assume-clean /dev/sdb4 /dev/sdc4  
/dev/sdd4 /dev/sde4 /dev/sdf4
mdadm: Raid level 5 not permitted with --build.

On the other hand there is the second RAID5 group which outputs the following:

------------------
# mdadm --examine /dev/sdg4
/dev/sdg4:
           Magic : a92b4efc
         Version : 00.91.00
            UUID : 384bd728:158c759c:e9be7911:01187b1f
   Creation Time : Tue Apr 24 18:14:48 2007
      Raid Level : raid5
   Used Dev Size : 241873792 (230.67 GiB 247.68 GB)
      Array Size : 967495168 (922.68 GiB 990.72 GB)
    Raid Devices : 5
   Total Devices : 6
Preferred Minor : 1

   Reshape pos'n : 0
       New Level : raid0
      New Layout : left-asymmetric
   New Chunksize : 0

     Update Time : Mon Nov 29 21:01:36 1999
           State : active
  Active Devices : 4
Working Devices : 6
  Failed Devices : 0
   Spare Devices : 2
        Checksum : 6eb7dc84 - correct
          Events : 0.65

          Layout : left-symmetric
      Chunk Size : 64K

       Number   Major   Minor   RaidDevice State
this     1      89        4        1      active sync

    0     0       0        0        0      faulty removed
    1     1      89        4        1      active sync
    2     2      90        4        2      active sync
    3     3      91        4        3      active sync
    4     4     120        4        4      active sync
    5     5     121        4        5      spare
    6     6      88        4        6      spare
------------------------------------
The 2nd RAID5 group was composed by 7 disks (I believed, as shown  
above). 1 disks is faulty and 2 disks are spare. But even though with  
the remaining 4 disks I could try to assemble the RAID5, but I have  
the same result as with the 1st RAID5. (mdadm: Failed to restore  
critical section for reshape, sorry.)

Do you have any idea on how to re-assemble this RAID 50 array ?

Thanks for any advice & help.

Nicolas

PS:

# mdadm -V
mdadm - v2.6 - 21 December 2006

Linux lab-suse 2.6.16.46-0.12-smp #1 SMP Thu May 17 14:00:09 UTC 2007  
x86_64 x86_64 x86_64 GNU/Linux