hard disk problem: bad superblock/group descriptors corrupted

**jcmag** · December 12th, 2008

I've an USB external hard drive that I can't mount anymore. I've the following error:

Code:

jc@jc-laptop:~$ dmesg | tail
[  994.739118] sd 2:0:0:0: [sdc] Assuming drive cache: write through
[  994.739844] sd 2:0:0:0: [sdc] 976773168 512-byte hardware sectors (500108 MB)
[  994.740606] sd 2:0:0:0: [sdc] Write Protect is off
[  994.740610] sd 2:0:0:0: [sdc] Mode Sense: 00 38 00 00
[  994.740613] sd 2:0:0:0: [sdc] Assuming drive cache: write through
[  994.740619]  sdc: sdc1
[  994.772810] sd 2:0:0:0: [sdc] Attached SCSI disk
[  994.773151] sd 2:0:0:0: Attached scsi generic sg2 type 0
[  995.199847] EXT3-fs error (device sdc1): ext3_check_descriptors: Inode table for group 912 not in group (block 0)!
[  995.200606] EXT3-fs: group descriptors corrupted!

e2fsck told me the superblock was bad ; after searching on the web I did the following:

Code:

sudo e2fsck -y -v -b 71663616 /dev/sdc1

using all superblocks given by:

Code:

jc@jc-laptop:~$ sudo mke2fs -n /dev/sdc1
mke2fs 1.41.3 (12-Oct-2008)
Étiquette de système de fichiers=
Type de système d'exploitation*: Linux
Taille de bloc=4096 (log=2)
Taille de fragment=4096 (log=2)
30531584 i-noeuds, 122096000 blocs
6104800 blocs (5.00%) réservés pour le super utilisateur
Premier bloc de données=0
Nombre maximum de blocs du système de fichiers=0
3727 groupes de blocs
32768 blocs par groupe, 32768 fragments par groupe
8192 i-noeuds par groupe
Superblocs de secours stockés sur les blocs*: 
	32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
	4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968, 
	102400000

But I always have the same error. What could I do now?

**caljohnsmith** · December 12th, 2008

You might have to resort to using some program like photorec to recover your files off the HDD, and then reformat the partition. I would run a HDD diagnostic test on that drive though to make sure it isn't having hardware problems. If you would like help running a "SMART" HDD diagnostic test on the drive from the Ubuntu command line, let me know and I can give you specific directions if you want. Good luck and let me know how it goes.

**jcmag** · December 14th, 2008

I'd prefer to try to fix the problems because recovery tools don't recover .vmdk files (vmware virtual machines) and they lose the folder hierarchy, as my hard disk is a backup disk these two features are very important to me.

I think I tried to do SMART test but I don't remember exactly what I did, do you have specific commands to try ?

**caljohnsmith** · December 14th, 2008

OK, to run a SMART HDD test, first open a terminal and do:

Code:

sudo apt-get install smartmontools

First do the following to save the current health status parameters of your HDD to a file on your desktop:

Code:

sudo smartctl -a /dev/sdc > ~/Desktop/sdc_health_before_test.txt

Then run:

Code:

sudo smartctl -t long /dev/sdc

That command will immediately terminate while the HDD begins its self-test, and it could take quite a while. You can monitor the progress with:

Code:

sudo smartctl -a /dev/sdc | grep -A 1 -i "self-test execution status"

Once the above command says the test is done, then do:

Code:

sudo smartctl -a /dev/sdc > ~/Desktop/sdc_health_after_test.txt
sudo smartctl -H /dev/sdc

And please post the contents of the two files on your desktop so I can see the results.

**jcmag** · December 14th, 2008

My hard disk doesn't seem to support SMART, maybe because it's an USB external hard disk?

Code:

jc@jc-laptop:~$ sudo smartctl -a /dev/sdc
smartctl version 5.38 [i686-pc-linux-gnu] Copyright (C) 2002-8 Bruce Allen
Home page is http://smartmontools.sourceforge.net/

Device: SAMSUNG  HD501LJ          Version: 0-10
Device type: disk
Local Time is: Sun Dec 14 20:00:10 2008 CET
Device does not support SMART

Error Counter logging not supported
Device does not support Self Test logging

**caljohnsmith** · December 14th, 2008

It looks like you are probably right about the drive not supporting a SMART test, but you could try each of the following and see if it gets you any further:

Code:

sudo smartctl -F samsung -a /dev/sdc
sudo smartctl -F samsung2 -a /dev/sdc
sudo smartctl -F samsung3 -a /dev/sdc

Let me know what those return.

**jcmag** · December 14th, 2008

Same message as above, for the three commands

**caljohnsmith** · December 14th, 2008

I think you would have to visit Samsung's website, because they most likely have their own software for testing that particular model you have. Good luck though, sorry I can't help out any more than that.