Yet another filesystem question. I wanted to use a USB drive that I hadn't mounted for a month or so and was surprised by the fact Ubuntu was unable to mount it. I looked it up in the disk utility and it said it discovered a device with 17 MB instead of 2 GB. The hardware looks intact, I hope for the best for repairing the ext4 filesystem.
I followed the instructions from HOWTO: Repair a broken Ext4 Superblock in Ubuntu, but I wasn't successful.
# fsck.ext4 -v /dev/sdb
e2fsck 1.42.5 (29-Jul-2012)
ext2fs_open2: Bad magic number in super-block
fsck.ext4: Superblock invalid, trying backup blocks...
fsck.ext4: Bad magic number in super-block while trying to open /dev/sdbThe 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
Filesystem blocks are invalid, however when I run the recommended solution to try the alternate superblock, I get the following output:
# e2fsck -b 8193 /dev/sdb
e2fsck 1.42.5 (29-Jul-2012)
e2fsck: Invalid argument while trying to open /dev/sdb
plus the same error message as in the last paragraph above.
Any ideas how to recover the drive?
Thank you very much!
Edit: testdisk
won't help. I'm still stunned why the tools only discover 17 MB.
The gparted feature "Attempt Data Rescue" yielded no results, no filesystems were identified.
@Colin According to disc utility, the device is unpartitioned, I can only deal with devices at the moment. It's the question if the partition table or the filesystem is damaged. Running fsck with partition gives
fsck.ext2: No such file or directory while trying to open /dev/sdb1
Possibly non-existent device?
@John
# sudo dd if=/dev/sdb bs=512 count=1 | hd
00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
1+0 records in
1+0 records out
512 bytes (512 B) copied, 0.00307007 s, 167 kB/s
00000200
Since all are zeros, this means no remains of MBR?
The result was there quite quick.
sudo hd /dev/sdb | less
00000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
*
01000000
It's all zero. I guess the pendrive broke down lying in a drawer in a magical, unexplainable way.
sudo dd if=/dev/sdb bs=512 count=1 | hd
to see if there is a remnant of an MBR there.