Re: Brocken Raid & LUKS

On 02/21/2013 12:47 PM, Stone wrote:

Am 21.02.2013 18:36, schrieb Phil Turmel:

quoted

But it does give you the locations of the backup superblocks.  Use these
numbers, starting with 32768, as "xxxx" in:

fsck.ext4 -n -b xxxx /dev

Once you give it a superblock that hasn't been corrupted, it should be
able to check the rest of the filesystem.  There will be damage near the
beginning, and probably more damage where you had to put zeros.

If it looks like that, do it again without "-n" to actually fix it.

Phil

ok. i think i dont understand you not complete.
i restore now the superblock with --> fsck.ext4 -bv 4096000
/dev/mapper/md2_nas

No!  You must keep using "-n" until you have seen a mostly-clean report!
 We don't know yet that the chunk size is right.

Leaving off "-n" will simultaneously fix the superblock (and all other
backup copies) and continue to fix the rest of the filesystem.  You
mustn't do that with a wrong chunk size--it will damage much more.

when this is done i make full filesystemcheck --> fsck.ext4 /dev/md2_nas
and answer the quest questions.

right?

No.

Just do the "fsck -n -b xxxx" combinations until you find a good
superblock.  That report will also show if there are many other errors.
 Expect scattered damage in the region < 384MB due to the wrong data
offset.  After that, there should only be errors where the new zeros
are, and maybe a few scattered errors from the original crash.  If there
many more errors, you have the wrong chunk size.

Phil