[gentoo-user] unformat a partition

[gentoo-user] unformat a partition

[Nick Smith]

i just accidentally blew away my ntfs partition with the gentoo
install cd (formatted hda1 instead of hdb1) is there a way to unformat
if it was just done? like undo the format information? i formatted
with ext3.  ordinarily i wouldnt mind, but i have some VERY important
information on there and a ton of pictures i cannot lose (originals). 
i can probably use getdataback when i get home just wanted to know if
there was another way since im still at the prompt on the install cd
now.

thanks (bangs head on wall)

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[gentoo-user] Re: unformat a partition

[Peter]

On Thu, 16 Mar 2006 12:15:24 -0500, Nick Smith wrote:

> i just accidentally blew away my ntfs partition with the gentoo
> install cd (formatted hda1 instead of hdb1) is there a way to unformat
> if it was just done? like undo the format information? i formatted
> with ext3.  ordinarily i wouldnt mind, but i have some VERY important
> information on there and a ton of pictures i cannot lose (originals). 
> i can probably use getdataback when i get home just wanted to know if
> there was another way since im still at the prompt on the install cd
> now.
> 
> thanks (bangs head on wall)

A definite MAYBE. If you did a quick format, not doing error checking,
there is an excellent chance your data is intact. If you did error
checking, then probably not, although badblock normally restores data as
it checks each sector.

If you know about partition editing, then go in and change the partition
type back to ntfs and see if it can be mounted by Windows or linux.

Now, first thing I would do is do an image backup of the partition just so
you can save it and try again with a different approach if need be.

Second, the sfdisk utility in Linux allows for low level partition
editing, but it's not easy. Windows utilities are much better for this
kind of thing. I remember the old Norton Disk Doctor for example.

Nonetheless, the good news is if you did a quick format, you most likely
will be fine. How fine depends on whether or not you can get the partition
to mount again under the original partition type.

Otherwise, there are services like Ontrack which, for mega $$$ get your
stuff back.

Good luck!

-- 
Peter


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Re: [gentoo-user] unformat a partition

[Robert Persson]

On Thursday 16 March 2006 09:15 Nick Smith was like:
> i just accidentally blew away my ntfs partition with the gentoo
> install cd (formatted hda1 instead of hdb1) is there a way to unformat
> if it was just done? like undo the format information? i formatted
> with ext3.

IMPORTANT: Please don't follow the following advice until you have had a 
second opinion from someone else—I think this will work, but I can't swear it 
will:

Reformat to NTFS and then use a recovery tool. If I remember right, windows 
fdisk is pretty insistent on doing a low level format, so you would be safer 
using the gnu tool for formatting. I don't know whether the gnu ntfs tools 
are up to the recovery job, or whether you need to use something proprietary.

If you are lucky you may be able to read the old data on the newly created 
partition without needing to use a recovery tool (I was able to do that with 
a linux partition once—can't remember if it was reiserfs or ext3), but I 
would copy all the files somewhere safe in any case because even very minor 
corruption could come back to haunt you later (as many theologians never tire 
of reminding us).
-- 
Robert Persson

Conspiracy Bears:
Once upon a time there were lots of conspiracy bears...


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[gentoo-user] Re: unformat a partition

[Peter]

On Thu, 16 Mar 2006 14:54:33 -0800, Robert Persson wrote:

> On Thursday 16 March 2006 09:15 Nick Smith was like:
>> i just accidentally blew away my ntfs partition with the gentoo
>> install cd (formatted hda1 instead of hdb1) is there a way to unformat
>> if it was just done? like undo the format information? i formatted
>> with ext3.
> 
> IMPORTANT: Please don't follow the following advice until you have had a 
> second opinion from someone else—I think this will work, but I can't swear it 
> will:
> 
Good advice...

> Reformat to NTFS and then use a recovery tool. If I remember right, windows 
> fdisk is pretty insistent on doing a low level format, so you would be safer 
> using the gnu tool for formatting. I don't know whether the gnu ntfs tools 
> are up to the recovery job, or whether you need to use something proprietary.
> 
No. fdisk does not formatting at all. It just writes to the partition
table. People run fdisk /mbr for example to rewrite the master partition
table.

I still think it may be better to edit the partition table directly and
change the filetype of the partition to NTFS: type 0x07.

Even if cfdisk you can change the type on the fly. Then reboot and see if
you can mount it. fdisk is non-destructive to the partition's data. It's
the format command where you have to make a choice to do a quick format or
a complete one. A quick format does not erase data, but does clean out the
fat tables. If that happens, you will have to extract the data manually.

Try the cfdisk trick first. Then, experiment with some of the myriad
Windows tools.

Remember to make a full image of the partition in question and the
partition table before trying these changes so you can go back to square 1
if need be.


> If you are lucky you may be able to read the old data
on the newly
> created partition without needing to use a recovery tool (I was able to
> do that with a linux partition once—can't remember if it was reiserfs
> or ext3), but I would copy all the files somewhere safe in any case
> because even very minor corruption could come back to haunt you later
> (as many theologians never tire of reminding us). -- Robert Persson
> 
> Conspiracy Bears:
> Once upon a time there were lots of conspiracy bears...

-- 
Peter


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Re: [gentoo-user] Re: unformat a partition

[Nick Smith]

thanks for the replies, i was actually able to get the data off the
drive with getdataback, i can rest easy now.

thanks again

Nick

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[gentoo-user] Re: Re: unformat a partition

[Peter]

On Fri, 17 Mar 2006 10:09:37 -0500, Nick Smith wrote:

> thanks for the replies, i was actually able to get the data off the
> drive with getdataback, i can rest easy now.
> 
> thanks again
> 
> Nick

Aren't you the lucky one!! Bet you'll never do _that_ again! However, it's
important to have a list of useful programs that help in just this kind of
circumstance. You _never_ know when you may need it. I'd never heard of
getdataback, but will take a look.

Glad this had a happy ending. Now, you should develop a good backup
routine.

-- 
Peter


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Re: [gentoo-user] Re: Re: unformat a partition

[Nick Smith]

>
> Aren't you the lucky one!! Bet you'll never do _that_ again! However, it's
> important to have a list of useful programs that help in just this kind of
> circumstance. You _never_ know when you may need it. I'd never heard of
> getdataback, but will take a look.
>
> Glad this had a happy ending. Now, you should develop a good backup
> routine.
>
> --
>
well i had one, i was keeping multiple copies of my files on shares
over my network, but over time i had alot of different versions of my
files, i moved them all onto my laptop so i could consolidate them and
then move them back onto my server, but at the same time was playing
with installing gentoo on this new laptop.  ive never had two HDs in a
laptop before and without thinking did mke2fs -j /dev/hda1 during the
install and blew away my ntfs partition that i was going to dual boot
and that had all my freshly moved files on  ;-)
i cant believe i was that incredibly stupid, but yes i hope i never do
that again.  getting in a hurry only makes problems.

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