Re: [vox-tech] AAARRRGGGHHHH! (Translation: Linux got hosed)

[Ted Deppner <ted@psybeMAPSr.com>]

On Wed, May 09, 2001 at 08:27:45PM -0700, Mark K. Kim wrote:
> > what makes you think the root partition is hosed?
> 
> So I rebooted, hoping the second boot re-recognize the partition modified
> by fsck.  Didn't work.  Didn't boot at all, actually -- kernel panic.
> 
> I think the partition is hosed.  I don't mind reinstalling the root
> partition -- just root files (plus some configuration in /etc, but... oh
> well.)

FYI... I've never lost a linux partition.  Ever.  In 8 or 9 years.  Well,
there was one, but the HD melted, so I don't count that.

Point being, you might try removing the disk to another linux box and
fscking it there.  If you have physical damage to the HD, you can still
pull the usable data off using dd (and the a conv= switch), and then fsck
the resulting dataset.

That'll cover you for partion and ext2fs.  If you blew your RPM databases
or something else that'd be distro specific you may then have to
reinstall... but linux and e2fs I can't even imagine being unrecoverable
when you can still access other parts of the drive.  I would trust that
windows e2fsexplorer to be a good indicator of filesystem states either,
but that's probably no surpise.



dd if=/dev/deaddrivepartion ibs=512 conv=noerror,sync \
        of=whereveryoulike obs=10k

512byte reads to get as much good sectors as possible (this is slower than
10k reads of course).  conv=noerror means don't fail on read errors, and
sync is use to pad less than ibs size input blocks to full ibs size
(handles short reads).

you can e2fsck and mount a extfs-formated file just as easily as a
partition, so using of=/tmp/mye2fsckdump is very useful.

And finally, use a rescue disk if you can't move the media around to
another working linux box.


I hope that helps and doesn't overwhelm.  I can clarify anything if you
like.

PS  I even recovered an entire disk where sector 0 had been destroyed!
dd and some patience go a long way.

-- 
Ted Deppner
http://www.psyber.com/~ted/