botched RAID, now e2fsck or what?

[tytso at mit.edu]

On Tue, Dec 08, 2009 at 11:48:18AM -0500, Lucian Șandor wrote:
> 
> Now, I am trying to re-create the array in the proper order. It takes
> me countless attempts, through hundreds of permutations. I am doing it
> programatically, but I don't think I have the right tool.

Something that may help is to use the findsuper program, in the
e2fsprogs sources; it's not built by default, but you can build it by
hand.  Each of the backup superblocks has a group number in one of the
fields, if it was created with a relatively modern mke2fs, so you can
use it to get information like this:

byte_offset  byte_start     byte_end  fs_blocks blksz  grp  last_mount_time           sb_uuid label
       1024           0  95999229952   23437312  4096    0  Thu Dec 10 00:24:39 2009 fd5210bd 
  134217728           0  95999229952   23437312  4096    1  Wed Dec 31 19:00:00 1969 fd5210bd 
  402653184           0  95999229952   23437312  4096    3  Wed Dec 31 19:00:00 1969 fd5210bd 
  671088640           0  95999229952   23437312  4096    5  Wed Dec 31 19:00:00 1969 fd5210bd 


The group number information should help you determine the order of the
disks in the raid array.

Good luck!

						- Ted