sda2 is corrupted (HOWTO NOT HELP)

[Jim]

On 07/06/2012 12:20 PM, Rick Stevens wrote:
> On 07/06/2012 08:22 AM, Jim issued this missive::
>> On 07/06/2012 11:09 AM, Reindl Harald wrote:
>>>
>>> Am 06.07.2012 17:01, schrieb Reindl Harald:
>>>>
>>>> Am 06.07.2012 16:11, schrieb Jim:
>>>>> On 07/05/2012 01:30 PM, Reindl Harald wrote:
>>>>>>> I have tried to use fedora and Gparted with no luck
>>>>>> you should not play around before
>>>>>> knowing what problem the drive has
>>>>>>
>>>>>> if it is a physical problem google for "ddrescue"
>>>>>>
>>>>>>> There are some important data files  I must save off of sda2
>>>>>> what about BACKUPS?
>>>>>>
>>>>>> ff your data is important backups exists
>>>>>> if your data is not important it does not matter
>>>>>>
>>>>>> why do people still need to learn it the hard way?
>>>>>>
>>>>> I run  dd if=/dev/sda2 of=/dev/sdb1  to copy, supposely a 26gb 
>>>>> image to sdb1 but i do not see a image on  sdb1 .
>>>>>
>>>>> Confused ???
>>>> no, just stupid because you do not read manuals nor know anything 
>>>> about
>>>> basic-commands and that is why you destroyed /dev/sdb1 if there were
>>>> data by overwrite the whole partition
>>>>
>>>> /dev/sdb1 is now a blockwise copy of /dev/sd1
>>>>
>>>> if you want a image you have to use "dd if=/deV7sda1 
>>>> of=/path/filename.image"
>>> well, i guess the reason why this happened was a combination
>>> of plain stupid advise below without explain what it does in
>>> a real dangerous way and blindly following any advise without
>>> trying to understand what are you doing
>>>
>>> hopefully lesson learned -> BOTH of you!
>>>
>>> this is why i said "google for ddrescue" and NOT provide any
>>> HIGH DANGEROUS command line
>>>
>>> -------- Original-Nachricht --------
>>> Betreff: Re: sda2 is corrupted
>>> Datum: Thu, 5 Jul 2012 20:15:14 +0200
>>> Von: Heinz Diehl<htd at fritha.org>
>>> Antwort an: Community support for Fedora 
>>> users<users at lists.fedoraproject.org>
>>> Organisation: private site
>>> An:users at lists.fedoraproject.org
>>>
>>> On 05.07.2012, Jim wrote:
>>>
>>>> There are some important data files  I must save off of sda2
>>> Before you start any rescueing, take a full snapshot of the partition,
>>> e.g. "dd if=/dev/sda2 of=/dev/on_an_external_disk"
>>>
>>>
>>>
>> that is exactly what I did but nothing shows up on /dev/sdb1 external
>> drive after dd has completed .
>
> Jim, what the others are trying to say (and several of them not too 
> gracefully) is that the command you ran simply did a block-for-block
> copy of /dev/sda2 over the top of /dev/sdb1.  /dev/sdb1 is now an exact
> copy of /dev/sda2 and whatever was on /dev/sdb1 has now been destroyed.
>
> You need to re-create a filesystem on that /dev/sdb1 partition. Plug the
> drive in and (as root) recreate the filesystem:
>
>     mke2fs -t ext4 /dev/sdb1
>
> When that's done, mount /dev/sdb1 somewhere (usually there's a "/mnt"
> directory you can use). Example:
>
>     mount /dev/sdb1 /mnt
>
> Finally, you can do the copy by entering this command:
>
>     dd if=/dev/sda2 of=/mnt/driveimage.img
>
> This would create a file, "driveimage.img" in the "/mnt" directory 
> (and thus on /dev/sdb1). Once that's complete, you can unmount /dev/sdb1:
>
>     umount /mnt
>
> and unplug the drive to keep it safe. When that's all done, you can
> attempt to run the fsck on /dev/sda2.
> ----------------------------------------------------------------------
> - Rick Stevens, Systems Engineer, AllDigital ricks at alldigital.com -
> - AIM/Skype: therps2        ICQ: 22643734            Yahoo: origrps2 -
> - -
> -          Consciousness: that annoying time between naps.           -
> ----------------------------------------------------------------------
>
Thanks Rick
I have done all that you have said but now I'm running into read-only 
file systems, what command would I use to change the ro to rw on 
external hard drive sdb1 ?