Am 21.02.2013 20:12, schrieb Stone:

Am 21.02.2013 19:54, schrieb Phil Turmel:

quoted

On 02/21/2013 01:29 PM, Stone wrote:

quoted

Am 21.02.2013 19:11, schrieb Phil Turmel:

quoted

On 02/21/2013 01:08 PM, Stone wrote:

quoted

ok i have checked all superblocks but i get always the same message.
here one sample:
fsck.ext4 -n -b 644972544 /dev/mapper/md2_nas
e2fsck 1.41.14 (22-Dec-2010)
fsck.ext4: Invalid argument while trying to open /dev/mapper/md2_nas

The superblock could not be read or does not describe a correct ext2
filesystem.  If the device is valid and it really contains an ext2
filesystem (and not swap or ufs or something else), then the 
superblock
is corrupt, and you might try running e2fsck with an alternate
superblock:
      e2fsck -b 8193 <device>

You very likely have the wrong chunk size.

Close luks, stop md2, and re-create with --chunk=64

And then try to fsck again.  (Without -b at first.)

Phil

ok. with --chunk=64 i cannot open the luks.
in witch steps (chunk) should i continue?

That is a big surprise.  The luks signature should not move with chunk
size.  Please use "mdadm -E /dev/sdc1" to recheck your data offset.

sorry i forgot
  mdadm -E /dev/sdc1
/dev/sdc1:
           Magic : a92b4efc
         Version : 1.2
     Feature Map : 0x0
      Array UUID : e5ace834:7cbb3655:4fd2e7b8:3e07b6d3
            Name : ubuntu:2  (local to host ubuntu)
   Creation Time : Thu Feb 21 18:57:51 2013
      Raid Level : raid5
    Raid Devices : 4

  Avail Dev Size : 3907027037 (1863.02 GiB 2000.40 GB)
      Array Size : 11721071616 (5589.04 GiB 6001.19 GB)
   Used Dev Size : 3907023872 (1863.01 GiB 2000.40 GB)
     Data Offset : 2048 sectors
    Super Offset : 8 sectors
           State : clean
     Device UUID : 368e4744:35adf66a:826f9d1b:11c606b6

     Update Time : Thu Feb 21 18:57:51 2013
        Checksum : 558db826 - correct
          Events : 0

          Layout : left-symmetric
      Chunk Size : 512K

    Device Role : Active device 0
    Array State : AA.A ('A' == active, '.' == missing)

quoted

If that wasn't it, please show the hexdump for the entire luks
signature.  I'd like to see its payload offset.

Also, if you go back to --chunk=512, open the luks, you could run the
following command to find possible superblock locations:

hexdump -C /dev/mapper/md2_nas |egrep '^[0-9a-f]+30  .+  53 ef' >sb.lst

(May take a long time to read the whole array)

Phil

with --chunk=512 i can open the luks but i cannot found a good 
superblock.
yes i can run the hexdump but i think this runs 8 hours or longer.
start the hexdump?
can i try more today?