bad superblock

bad superblock – not a cool new band

Posted on November 11, 2010

Being an amateur sys admin when you should really hire a professional one is a constant source of new learnings.

Today, I learnt that hard drives can, like a manic teenager decide one day that they are now self-identifying as a bad superblock and will not be performing any of the tasks previously expected of them (like booting) and they’re keeping all your data as well.

What is a bad superblock? Wikipedia has it’s suggestions, my artists impression is above.

Can bad superblocks be made good again?….Is there hope for humanity?….

Kept you in suspense for a whole click….Yes!

Google is amazing as open source software communities – what a happy marriage.

The three posts that helped saved my ass today:

Here’s how it went, after some futile messing around.

To figure out which of the many things in /dev/ was actually the one I wanted

sudo testdisk 

Short-term borrowed a TB hard drive and to generate a recovered image:

 sudo ddrescue -r 3 sda1 /media/extdrive/image /media/extdrive/logfile 

Went to sleep waiting for the recovered image of my corrupted hard drive was formed that I should be able to recover data from….woke up….realized that like an idiot i hadn’t mounted my external hard drive and so the image was being made on my local hard disk and the disk ran out of space….groan.  Mounted the external hard drive and copied the image to the external drive.  Copying ~450GB takes 5.5 hours, but it did it.  Copied the log file too….repeated the above command….miracle it just picked up where it left off – hurrah.

So now I have an image of the recovered drive that I should be able to recover files from.

Instead of trying this, first I’m going to try recovering the hard disk now I have a backup image.

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Other things that were useful today (mostly for my reference)