[gentoo-user] Accidentally reformatted my EVMS root partition. Any hope of recovering data?

[gentoo-user] Accidentally reformatted my EVMS root partition. Any hope of recovering data?

[Robert Persson]

I have, much to my intense surprise, managed to reformat my root
partition unintentionally. It was an EVMS native reiserfs volume, but
now it is a normal xfs partition. I haven't, as far as I am aware,
written any files to it since the unfortunate accident.

The tool I used to create the xfs partition was a non-standard, and
quite possibly inferior one with non-standard behaviour. It is also
likely that the xfs partition ends at the 128gb (i.e. 137gb) point on
the disk due to the circumstances in which it was created, whereas the
original reiserfs partition extended beyond the 128gb point.

Is there any possibility of recovering some of the data (there are some
family photos and a few other things I would very much like to retrieve)
or should I just put it down to experience?

Many thanks in advance
Robert

P.S. In case you are wondering how I managed to do this, it was like
this: I need to run a video editing application and one or two other
things in windows 2000. The crossmeta virtual file system drivers
sounded like a good way of sharing the work areas between windows and
linux, especially given the unreliability of ntfs even in windows.
Unfortunately the crossmeta stuff is very poorly documented. Quite apart
from anything else, there is no indication that the drivers just don't
actually work at all, hence lots of pointless troubleshooting and a
boundless potential to create much bigger problems. Add to this the
unfamiliar device naming scheme of crossmeta, and the fact that windows
2000 doesn't, by default, support large drives, even though the disk
manager behaves as if it does, and you have a recipe for a very big ****
up. Honestly. How could I pass up such a splendid opportunity?

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Re: [gentoo-user] Accidentally reformatted my EVMS root partition. Any hope of recovering data?

[Iain Buchanan]

On Sun, 2006-09-24 at 17:47 -0700, Robert Persson wrote:
> I have, much to my intense surprise, managed to reformat my root
> partition unintentionally. It was an EVMS native reiserfs volume, but
> now it is a normal xfs partition. I haven't, as far as I am aware,
> written any files to it since the unfortunate accident.

did you actually _format_ it, or just repartition it?

I see three possible options:
1. repartition it, hoping the filesystem has not been touched
2. run an undelete tool on it (don't know if they exist for reiser,
certainly not for ext3
3. give up!

If you "formatted" it, ie wrote "zero's" all over the place (or whatever
a format does), then good luck, you'll need an "undelete", if there is
such a beast for reiser.

If you just repartitioned it (ie. wrote to the partition table that it
was now an xfs instead of reiserfs) and you've done nothing else, not
even mounted it since, then you _should_ just be able to use fdisk to
redo the partition table.

Use caution! I'd back up the drive with dd or something first, just in
case you screw it up.

repartitioning doesn't necessarily screw with the actual data on the
drive - just the partition table.  I once blew away my partition table
by mistake, and rebuilt it by trial and error by guessing how big the
partition where from memory, and then mounting them to see if I got it
right.

Of course, if you've run anything like mkfs over the partition then
you're probably screwed.

> The tool I used to create the xfs partition was a non-standard, and
> quite possibly inferior one with non-standard behaviour.

so long as it created the partition without mkfs-ing it!

> P.S. In case you are wondering how I managed to do this, it was like
> this:
[snip]
>  Honestly. How could I pass up such a splendid opportunity?

*lol* you can't let an opportunity like that pass by...

HTH.
-- 
Iain Buchanan <iaindb at netspace dot net dot au>

Surly to bed, surly to rise, makes you about average.

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Re: [gentoo-user] Accidentally reformatted my EVMS root partition. Any hope of recovering data?

[Robert Persson]

On Mon, 2006-25-09 at 10:44 +0930, Iain Buchanan wrote:
> so long as it created the partition without mkfs-ing it!

To paraphrase the immortal Captain Haddock, #*@#*#@!!!

;-) Robert

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Re: [gentoo-user] Accidentally reformatted my EVMS root partition. Any hope of recovering data?

[Wolfgang Illmeyer]

try running reiserfsck, with --rebuild-sb and/or --rebuild-tree, as needed. 
But keep a copy of the partition around (as mentioned in the other posting), 
just in case you find a better way to rescue your files.

/Wolfgang
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Re: [gentoo-user] Accidentally reformatted my EVMS root partition. Any hope of recovering data?

[Robert Persson]

On Tue, 2006-26-09 at 14:09 +0200, Wolfgang Illmeyer wrote:
> try running reiserfsck, with --rebuild-sb and/or --rebuild-tree, as needed. 
> But keep a copy of the partition around (as mentioned in the other posting), 
> just in case you find a better way to rescue your files

Good suggestion, Wolfgang. I did manage to recover a very small number
of useful files that way. I didn't back up the partition because it is
just too big to have hanging around taking up disk space.

The reiserfsck man page says that if you have used a repartioning tool
you need to find the correct start of the partition. I had guessed that
it would be where it was before, but it looks like I was wrong. What I
cannot find anywhere is any instructions on how actually to find the
start of the partition. If anyone knows the answer then please post it.
It won't help me, but it might help someone else with the same problem.

Thanks
Robert

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