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Roberto Ragusa 09-23-2012 02:03 PM

How to rescue your partitions after upgrade to Fedora 18 Alpha eats them
 
On 09/23/2012 01:33 PM, Jakub Kicinski wrote:

> I realised that MBR and GPT where wiped out and all of my partitions
> were nowhere to be found.

A useful habit to have:

fdisk -l /dev/sd? >save_this_file_away__it_could_be_important_some_d ay.txt


--
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"Eddie G. O'Connor Jr." 09-23-2012 04:09 PM

How to rescue your partitions after upgrade to Fedora 18 Alpha eats them
 
On 09/23/2012 07:33 AM, Jakub Kicinski
wrote:



Hi all,

I recently had a weird problem after "upgrade" to Fedora 18 Alpha. I
decided to share the solution, maybe it will help someone.

But first:

1. The rant

Clearly something bad is going on in Fedora world. I've been
upgrading to Alphas/Betas for years now and it never caused more
trouble than occasional need to rebuild some packages manually.

I read this:
http://lwn.net/Articles/506831/
but I didn't suspect that not only Rawhide, but also Alpha releases
became unusable.

First of all PreUpgrade crashes before it starts. I thought, well, I'll
try DVD. It kind of worked. I was looking for words like "upgrade" or
"update" in the new and shiny anaconda but no luck. Eventually it
started the installation (without any "Warning: write changes to
disk?" or alike). At that point partitions of Fedora 17 where already
magically renamed to Fedora 18, so I hoped for the best. Unfortunately
anaconda crashed when it tried to format my Win7 partition to the
widely used filesystem "None"?! Imagine my amusement when after reboot
I realised that MBR and GPT where wiped out and all of my partitions
were nowhere to be found.

2. The problem

It turned out anaconda not only wipes out MBR but also removes magic
numbers from partitions superblocks (anyone can explain why?). So the
good news was my data was still there, the bad news was: none of
automatic "lost partition detection" tool could find them (at least none
that I know of).

3. The solution

If it happens to you as well, here is what you can try to get your
data back:

a. Accept that you do all this on your own risk ;)
b. Backup your HDD, preferably all of it. Backup can be done with dd.
c. Connect damaged HDD to some other Linux box or use a Live
distribution.
d. Now you need to locate your first partition. There is a good chance
that this will be your /boot and Fedora usually locates it at
0x100000 (i.e. it starts in 2048 sector). Other possibility is
sector 63/64 from pre-GPT world.
e. Set magic value in superblock (see below).
f. Try mounting partition using offset option in mount.
g. Calculate where next partition is most likely to start using block
count and block size from superblock.
h. Fix your MBR. You can probably do that in parted or some similar
tool, but who would trust tools after one just nearly destroyed all
your data.
i. If you have more partitions to find, go back to (d).


Important: All values on disk are LITTLE ENDIAN.
Important: Try mounting your partitions read-only first.

Notes on EXT4.
Ext4 is quite easy to find. You will recognize it by two zeroed out
sectors (1024 bytes of zeroes) at the beginning of every partition.
NOTE: those zeroes are *in* the partition, do not skip them when trying
to mount. After zeroes there is a superblock. What you are looking
for is offset +0x38 in the superblock, where you once had a magic value
of 0xEF53, you will probably have to put it back there. More information
on EXT4:
https://ext4.wiki.kernel.org/index.php/Ext4_Disk_Layout

Notes on NTFS.
NTFS partition starts with EB 52 90, there are no zeroes in front. Magic
value which is removed by anaconda is "4E 54 46 53 20 20 20 20"
at offset 0x03 into a partition. Its literally "NTFS " (with spaces).
More info:
http://technet.microsoft.com/en-us/library/cc781134%28v=ws.10%29.aspx

Useful tools:
dd - will help you to copy blocks of data around. If you don't know it
already, I advise you to read some tutorial and practise first. It's
easy to destroy thing with one wrong dd.

emacs, okteta etc. - hex editor...

losetup - is a tool which enables you to mount files and drives at
particular offset as loop devices. Very useful, read more here:
http://rackerhacker.com/2010/12/14/mounting-a-raw-partition-file-made-with-dd-or-dd_rescue-in-linux/

dumpe2fs, nftsinfo - will decode superblock for you.

bash calculator - $((1+2+3+4*4)) can save you a lot of time.
bash printf - printf "%d
" 0x1AB2F or printf "%x
" $((7863*4096)) is
handy as well.

Good luck from (a sightly less happy) Fedora user
-- Kuba


WOW!.....that's terrible! But I guess that's just one of the reasons
I purposely wait until a release has been out for almost 3
months....before installing / upgrading. It just makes it a little
easier when the glitches have been made apparent and are either
completely worked out or are in the process of being worked out. In
all honesty...I actually prefer to wait a few releases before
upgrading, I kind of have my OWN "schedule" I usually wait and let
one release pass by, then I'll wait for the next version...and 3 to
4 months into that I'll upgrade.....this helps me remain a
little more "stable" and not have to scurry around upgrading every 6
months....





EGO II



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Roger 09-23-2012 11:22 PM

How to rescue your partitions after upgrade to Fedora 18 Alpha eats them
 
On 09/24/2012 02:09 AM, Eddie G.
O'Connor Jr. wrote:




On 09/23/2012 07:33 AM, Jakub
Kicinski wrote:



Hi all,

I recently had a weird problem after "upgrade" to Fedora 18 Alpha. I
decided to share the solution, maybe it will help someone.

But first:

1. The rant

Clearly something bad is going on in Fedora world. I've been
upgrading to Alphas/Betas for years now and it never caused more
trouble than occasional need to rebuild some packages manually.

I read this:
http://lwn.net/Articles/506831/
but I didn't suspect that not only Rawhide, but also Alpha releases
became unusable.

First of all PreUpgrade crashes before it starts. I thought, well, I'll
try DVD. It kind of worked. I was looking for words like "upgrade" or
"update" in the new and shiny anaconda but no luck. Eventually it
started the installation (without any "Warning: write changes to
disk?" or alike). At that point partitions of Fedora 17 where already
magically renamed to Fedora 18, so I hoped for the best. Unfortunately
anaconda crashed when it tried to format my Win7 partition to the
widely used filesystem "None"?! Imagine my amusement when after reboot
I realised that MBR and GPT where wiped out and all of my partitions
were nowhere to be found.

2. The problem

It turned out anaconda not only wipes out MBR but also removes magic
numbers from partitions superblocks (anyone can explain why?). So the
good news was my data was still there, the bad news was: none of
automatic "lost partition detection" tool could find them (at least none
that I know of).

3. The solution

If it happens to you as well, here is what you can try to get your
data back:

a. Accept that you do all this on your own risk ;)
b. Backup your HDD, preferably all of it. Backup can be done with dd.
c. Connect damaged HDD to some other Linux box or use a Live
distribution.
d. Now you need to locate your first partition. There is a good chance
that this will be your /boot and Fedora usually locates it at
0x100000 (i.e. it starts in 2048 sector). Other possibility is
sector 63/64 from pre-GPT world.
e. Set magic value in superblock (see below).
f. Try mounting partition using offset option in mount.
g. Calculate where next partition is most likely to start using block
count and block size from superblock.
h. Fix your MBR. You can probably do that in parted or some similar
tool, but who would trust tools after one just nearly destroyed all
your data.
i. If you have more partitions to find, go back to (d).


Important: All values on disk are LITTLE ENDIAN.
Important: Try mounting your partitions read-only first.

Notes on EXT4.
Ext4 is quite easy to find. You will recognize it by two zeroed out
sectors (1024 bytes of zeroes) at the beginning of every partition.
NOTE: those zeroes are *in* the partition, do not skip them when trying
to mount. After zeroes there is a superblock. What you are looking
for is offset +0x38 in the superblock, where you once had a magic value
of 0xEF53, you will probably have to put it back there. More information
on EXT4:
https://ext4.wiki.kernel.org/index.php/Ext4_Disk_Layout

Notes on NTFS.
NTFS partition starts with EB 52 90, there are no zeroes in front. Magic
value which is removed by anaconda is "4E 54 46 53 20 20 20 20"
at offset 0x03 into a partition. Its literally "NTFS " (with spaces).
More info:
http://technet.microsoft.com/en-us/library/cc781134%28v=ws.10%29.aspx

Useful tools:
dd - will help you to copy blocks of data around. If you don't know it
already, I advise you to read some tutorial and practise first. It's
easy to destroy thing with one wrong dd.

emacs, okteta etc. - hex editor...

losetup - is a tool which enables you to mount files and drives at
particular offset as loop devices. Very useful, read more here:
http://rackerhacker.com/2010/12/14/mounting-a-raw-partition-file-made-with-dd-or-dd_rescue-in-linux/

dumpe2fs, nftsinfo - will decode superblock for you.

bash calculator - $((1+2+3+4*4)) can save you a lot of time.
bash printf - printf "%d
" 0x1AB2F or printf "%x
" $((7863*4096)) is
handy as well.

Good luck from (a sightly less happy) Fedora user
-- Kuba


WOW!.....that's terrible! But I guess that's just one of the
reasons I purposely wait until a release has been out for almost 3
months....before installing / upgrading. It just makes it a little
easier when the glitches have been made apparent and are either
completely worked out or are in the process of being worked out.
In all honesty...I actually prefer to wait a few releases before
upgrading, I kind of have my OWN "schedule" I usually wait and let
one release pass by, then I'll wait for the next version...and 3
to 4 months into that I'll upgrade.....this helps me
remain a little more "stable" and not have to scurry around
upgrading every 6 months....





EGO II







Yes I am much the same. I'll skip an upgrade or two, wait for
stability then after copying all my files, do a fresh install.

Roger



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"Eddie G. O'Connor Jr." 09-23-2012 11:43 PM

How to rescue your partitions after upgrade to Fedora 18 Alpha eats them
 
On 09/23/2012 07:22 PM, Roger wrote:




On 09/24/2012 02:09 AM, Eddie G.
O'Connor Jr. wrote:




On 09/23/2012 07:33 AM, Jakub
Kicinski wrote:



Hi all,

I recently had a weird problem after "upgrade" to Fedora 18 Alpha. I
decided to share the solution, maybe it will help someone.

But first:

1. The rant

Clearly something bad is going on in Fedora world. I've been
upgrading to Alphas/Betas for years now and it never caused more
trouble than occasional need to rebuild some packages manually.

I read this:
http://lwn.net/Articles/506831/
but I didn't suspect that not only Rawhide, but also Alpha releases
became unusable.

First of all PreUpgrade crashes before it starts. I thought, well, I'll
try DVD. It kind of worked. I was looking for words like "upgrade" or
"update" in the new and shiny anaconda but no luck. Eventually it
started the installation (without any "Warning: write changes to
disk?" or alike). At that point partitions of Fedora 17 where already
magically renamed to Fedora 18, so I hoped for the best. Unfortunately
anaconda crashed when it tried to format my Win7 partition to the
widely used filesystem "None"?! Imagine my amusement when after reboot
I realised that MBR and GPT where wiped out and all of my partitions
were nowhere to be found.

2. The problem

It turned out anaconda not only wipes out MBR but also removes magic
numbers from partitions superblocks (anyone can explain why?). So the
good news was my data was still there, the bad news was: none of
automatic "lost partition detection" tool could find them (at least none
that I know of).

3. The solution

If it happens to you as well, here is what you can try to get your
data back:

a. Accept that you do all this on your own risk ;)
b. Backup your HDD, preferably all of it. Backup can be done with dd.
c. Connect damaged HDD to some other Linux box or use a Live
distribution.
d. Now you need to locate your first partition. There is a good chance
that this will be your /boot and Fedora usually locates it at
0x100000 (i.e. it starts in 2048 sector). Other possibility is
sector 63/64 from pre-GPT world.
e. Set magic value in superblock (see below).
f. Try mounting partition using offset option in mount.
g. Calculate where next partition is most likely to start using block
count and block size from superblock.
h. Fix your MBR. You can probably do that in parted or some similar
tool, but who would trust tools after one just nearly destroyed all
your data.
i. If you have more partitions to find, go back to (d).


Important: All values on disk are LITTLE ENDIAN.
Important: Try mounting your partitions read-only first.

Notes on EXT4.
Ext4 is quite easy to find. You will recognize it by two zeroed out
sectors (1024 bytes of zeroes) at the beginning of every partition.
NOTE: those zeroes are *in* the partition, do not skip them when trying
to mount. After zeroes there is a superblock. What you are looking
for is offset +0x38 in the superblock, where you once had a magic value
of 0xEF53, you will probably have to put it back there. More information
on EXT4:
https://ext4.wiki.kernel.org/index.php/Ext4_Disk_Layout

Notes on NTFS.
NTFS partition starts with EB 52 90, there are no zeroes in front. Magic
value which is removed by anaconda is "4E 54 46 53 20 20 20 20"
at offset 0x03 into a partition. Its literally "NTFS " (with spaces).
More info:
http://technet.microsoft.com/en-us/library/cc781134%28v=ws.10%29.aspx

Useful tools:
dd - will help you to copy blocks of data around. If you don't know it
already, I advise you to read some tutorial and practise first. It's
easy to destroy thing with one wrong dd.

emacs, okteta etc. - hex editor...

losetup - is a tool which enables you to mount files and drives at
particular offset as loop devices. Very useful, read more here:
http://rackerhacker.com/2010/12/14/mounting-a-raw-partition-file-made-with-dd-or-dd_rescue-in-linux/

dumpe2fs, nftsinfo - will decode superblock for you.

bash calculator - $((1+2+3+4*4)) can save you a lot of time.
bash printf - printf "%d
" 0x1AB2F or printf "%x
" $((7863*4096)) is
handy as well.

Good luck from (a sightly less happy) Fedora user
-- Kuba


WOW!.....that's terrible! But I guess that's just one of the
reasons I purposely wait until a release has been out for almost
3 months....before installing / upgrading. It just makes it a
little easier when the glitches have been made apparent and are
either completely worked out or are in the process of being
worked out. In all honesty...I actually prefer to wait a few
releases before upgrading, I kind of have my OWN "schedule" I
usually wait and let one release pass by, then I'll wait for the
next version...and 3 to 4 months into that I'll
upgrade.....this helps me remain a little more "stable" and not
have to scurry around upgrading every 6 months....





EGO II







Yes I am much the same. I'll skip an upgrade or two, wait for
stability then after copying all my files, do a fresh install.

Roger







It just seems that.....of all the different methods....THAT one is
the safest. I've accumulated quite a few "irreplaceable" files
throughout the years...and I'd hate to lose some or all of them due
to a restructuring of the build for the installer!..





EGO II



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Frank Murphy 09-24-2012 07:55 AM

How to rescue your partitions after upgrade to Fedora 18 Alpha eats them
 
On 24/09/12 00:43, Eddie G. O'Connor Jr. wrote:




It just seems that.....of all the different methods....THAT one is the
safest. I've accumulated quite a few "irreplaceable" files throughout
the years...and I'd hate to lose some or all of them due to a
restructuring of the build for the installer!..



External drive(s) may be a safer place to keep irreplacable files.
I use a simple Raid1 NAS for "must keep" files.

--
Regards,
Frank
"Jack of all, fubars"
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"Eddie G. O'Connor Jr." 09-24-2012 08:52 AM

How to rescue your partitions after upgrade to Fedora 18 Alpha eats them
 
On 09/24/2012 03:55 AM, Frank Murphy wrote:

On 24/09/12 00:43, Eddie G. O'Connor Jr. wrote:




It just seems that.....of all the different methods....THAT one is the
safest. I've accumulated quite a few "irreplaceable" files throughout
the years...and I'd hate to lose some or all of them due to a
restructuring of the build for the installer!..



External drive(s) may be a safer place to keep irreplacable files.
I use a simple Raid1 NAS for "must keep" files.

Oh I agree TOTALLY! Although I have like over a thousand files that are
directly stored on my PC I ALSO have them stored on a 1TB drive in an
encrypted folder, so should anything ever happen, I can put back what's
lost or corrupted. Also I run the "Backup" tool every month, with
incremental backups between the monthly ones. I do NOT intend on losing
data EVER again! The last time I DID lose data was when I was going from
"Windows" to Linux, and ever since losing some very "vintage" guitar
sounds from my Cakewalk days, I've never done ANYTHING without a backup
made first.


On a totally different note, but related just the same...because of all
the files I have now I'm thinking maybe it's time for a "dedicated
server" to hold them all, can someone recommend an OS/distro that would
handle this along with possible "printer duties" and "security" that
will be easy to use and "light" on the hardware?....(and just FYI I have
no command line/scripting skills so something with a GUI would be
preferred!...)



EGO II
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Patrick O'Callaghan 09-24-2012 12:39 PM

How to rescue your partitions after upgrade to Fedora 18 Alpha eats them
 
On Sun, 2012-09-23 at 13:33 +0200, Jakub Kicinski wrote:
> I recently had a weird problem after "upgrade" to Fedora 18 Alpha. I
> decided to share the solution, maybe it will help someone.

This should be posted to the Fedora test list, not here. F18 is not a
released system.

poc

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"Mikkel L. Ellertson" 09-24-2012 01:36 PM

How to rescue your partitions after upgrade to Fedora 18 Alpha eats them
 
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 09/24/2012 07:39 AM, Patrick O'Callaghan wrote:
> On Sun, 2012-09-23 at 13:33 +0200, Jakub Kicinski wrote:
>> I recently had a weird problem after "upgrade" to Fedora 18 Alpha. I
>> decided to share the solution, maybe it will help someone.
>
> This should be posted to the Fedora test list, not here. F18 is not a
> released system.
>
> poc
>
One program I did not see talked about is testdisk. It is designed
to find deleted partitions. I have not needed to use it for real,
but I have deliberately messed up a partition table to see how well
it works. It does a great job on drives that have only been
partitioned and formatted once. If you have had different
partitioning sachems, you may have to pick out the correct
partitions from a list of partitions it finds. But it usually isn't
too hard.

Mikkel
- --
Do not meddle in the affairs of dragons, for thou art crunchy and
taste good with Ketchup!
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=0ClG
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Jakub Kicinski 09-24-2012 11:43 PM

How to rescue your partitions after upgrade to Fedora 18 Alpha eats them
 
On Mon, 24 Sep 2012 08:36:41 -0500, "Mikkel L. Ellertson"
<mellertson@gmail.com> wrote:

>On 09/24/2012 07:39 AM, Patrick O'Callaghan wrote:
>> On Sun, 2012-09-23 at 13:33 +0200, Jakub Kicinski wrote:
>>> I recently had a weird problem after "upgrade" to Fedora 18 Alpha. I
>>> decided to share the solution, maybe it will help someone.
>>
>> This should be posted to the Fedora test list, not here. F18 is not a
>> released system.
>>
>> poc
>>
>One program I did not see talked about is testdisk. It is designed
>to find deleted partitions. I have not needed to use it for real,
>but I have deliberately messed up a partition table to see how well
>it works. It does a great job on drives that have only been
>partitioned and formatted once. If you have had different
>partitioning sachems, you may have to pick out the correct
>partitions from a list of partitions it finds. But it usually isn't
>too hard.

Well I didn't mention it because I said:

> anaconda [...] removes magic numbers from partitions superblocks [...]
and
> none of automatic "lost partition detection" tool could find them.

I tried testdisk with a few different settings, none of them worked.
Only partition it was kind of able to detect was the first on (/boot)
and even there it messed up starting point (2046 instead of 2048
sector).

But yes, nevertheless, if someone "just" wipes out his MBR testdisk
would be very useful I agree.

-- Kuba
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Jakub Kicinski 09-24-2012 11:44 PM

How to rescue your partitions after upgrade to Fedora 18 Alpha eats them
 
On Mon, 24 Sep 2012 08:09:11 -0430, Patrick O'Callaghan
<pocallaghan@gmail.com> wrote:

>On Sun, 2012-09-23 at 13:33 +0200, Jakub Kicinski wrote:
>> I recently had a weird problem after "upgrade" to Fedora 18 Alpha. I
>> decided to share the solution, maybe it will help someone.
>
>This should be posted to the Fedora test list, not here. F18 is not a
>released system.

Sorry, won't happen again.

-- Kuba
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