Overwritten partition

Overwritten partition

[hallexh]

Hello,

I accidentally overwritten first 40GB of 36TB XFS partition. I ran
xfs_repair then, which resets the superblocks (I'm sorry i didn't copied
the output of it) and after I mounted the partition, there was no files.
Empty file system, but It should be almost 90% full.

Am I really screwed or there's a chance to recover the data somehow?

Thanks anyone for helping!
John

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Re: Overwritten partition

[Emmanuel Florac]

Le Sun, 31 May 2015 00:48:05 +0200
hallexh@gmail.com écrivait:

> I accidentally overwritten first 40GB of 36TB XFS partition. I ran
> xfs_repair then, which resets the superblocks (I'm sorry i didn't
> copied the output of it) and after I mounted the partition, there was
> no files. Empty file system, but It should be almost 90% full.
> 
> Am I really screwed or there's a chance to recover the data somehow?

At this point your best bet is to use a tool like photorec on the
partition to see what data it can salvage, though on 36 TB sorting the
results may be overwhelming... You'll need some other large filesystem
to store the salvaged data, though.

-- 
------------------------------------------------------------------------
Emmanuel Florac     |   Direction technique
                    |   Intellique
                    |	<eflorac@intellique.com>
                    |   +33 1 78 94 84 02
------------------------------------------------------------------------

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Re: Overwritten partition

[Greg Freemyer]

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On Mon, Jun 1, 2015 at 7:13 AM, Emmanuel Florac <eflorac@intellique.com>
wrote:

> Le Sun, 31 May 2015 00:48:05 +0200
> hallexh@gmail.com écrivait:
>
> > I accidentally overwritten first 40GB of 36TB XFS partition. I ran
> > xfs_repair then, which resets the superblocks (I'm sorry i didn't
> > copied the output of it) and after I mounted the partition, there was
> > no files. Empty file system, but It should be almost 90% full.
> >
> > Am I really screwed or there's a chance to recover the data somehow?
>
> At this point your best bet is to use a tool like photorec on the
> partition to see what data it can salvage, though on 36 TB sorting the
> results may be overwhelming... You'll need some other large filesystem
> to store the salvaged data, though.


Photorec doesn't recreate any filesystem metadata (filenames, directory
structure, timestamps, etc).

Hopefully you have a recent backup you can use instead of trying to go
through Photorec's results.

Greg

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Re: Overwritten partition

[Dave Chinner]

On Sun, May 31, 2015 at 12:48:05AM +0200, hallexh@gmail.com wrote:
> Hello,
> 
> I accidentally overwritten first 40GB of 36TB XFS partition. I ran
> xfs_repair then, which resets the superblocks (I'm sorry i didn't copied
> the output of it) and after I mounted the partition, there was no files.
> Empty file system, but It should be almost 90% full.

SOunds like a case of using inode32 allocator, and losing the entire
inode btree (i.e. the index that tracks allocated inodes) as well as
the root inode, hence there being no way to easily discover and
reconstruct the directory tree at all.

> Am I really screwed or there's a chance to recover the data
> somehow?

disaster recovery tools are your only real hope at this point. go
searching for xfs_irecover as a good starting point for scraping
inodes out of the corpse and hence hopefully being able to
reconstruct some of the directory structure...

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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