Trying to recover a bad superblock

[Frank616]

I have had a problem with my 14.04 hanging on shutdown with a complaint mount: / is busy. This forces me to use the 'big red button' to shut down, which often corrupts the system disk, forcing a safe boot, and run of fsck to get it going again. Except this time, fsck failed. It too got 'stuck'. (This is listed in another post here)

Trying to use a root console from the safe mode boot is not my forte, but I went there, and tried running fsck on /dev/sdb2, and I get a report of a short read. Using that as a basis for googling, I came across this:

http://unix.stackexchange.com/questi...open-partition

The last poster in that thread suggests a bad superblock as the reason why the main portion of the drive appears to be only 1K in size. The drive is a 60 GB OCZ Vertex Plus SSD just over a year old.

There should be backup superblocks, and I am trying to restore one of them. However, I got stopped early in the above troubleshooting guide trying to determine the block size, as the drive is mounted, and umount does not seem to work. Now, this may be simply because I cannot work on a disk that contains the system while it is running that system. However, I am not sure of that. I know just enough about command line stuff to be dangerous.

Any suggestions of how to recover this disk?

I can just reinstall on another disk, or even on this same one, and that may be the easier course. All my data is on the mechanical drive in the machine anyway.

Thanks for any suggestions you may be able to offer.

Frank.

[vinnywright]

no ,,,,,,,,,you can not work on a mounted and running partition ,,,,,,,,,,that is to say if sdb1 is the system you are running ,,,you can not do any thing to it .

boot to a system on a different partition/drive or use a live-usb/cd a gparted disk would be good hear and it has a check drive feature .

VINNY

[Frank616]

Vinny:

Thought as much. I'll try gparted and get back to you.

Frank.

[oshunluvr]

Testdisk may help also. I think it's on the gparted live ISO. Test disk can read the backup superblocks and fix the main one.

If all else fails; for MBR disks there are backups of the superblock located on the drive. Backup locations are: 8193, 32768, 98304, 163840, 229376 and 294912. 8193 is not likely used on newer systems. 32768 is the most common position for the first backup.

This command:

e2fsck -b 32768 /dev/sdb2

will cause the filesystem to use the superblock stored in that backup location.
If the check was successful it will restore the backup to position 0.
If this is not working try using the other copy of Superblock listed at the above locations.

[Frank616]

ohsunluvr and vinny:

Tried the e2fsck command to a backup of the superblock. It reports that the superblock is absent or bad.

I am going to throw in the towel on this one. I just realized that I had formatted that system drive ext2 to try to reduce writes to a cheap 60 GB SSD. Not worth any further effort. I went and bought a 500 GB Samsung EVO 850 for my 11" laptop, and I'm moving the 256 GB EVO 850 to this desktop machine as a system drive. More on that in another thread, as GRUB on the drive taken from the laptop keeps wanting to boot Windows on this multi drive desktop machine. Watch for a new thread in the 14.04 post installation section.

Frank.

[oshunluvr]

500 GB Samsung EVO 850

Sweet...

I have 2x Samsung 840 PRO 256GB drives in my desktop. In RAID0 via btrfs. Also Sweet....