sda1 corrupted and unmountable

[sanjayak]

The suggestion was to download another version of UNIX (called Slax) from http://www.slax.org/ , burn a CD (or prepare a USB device), and boot from that, instead of Ubuntu live CD. Supposedly it won't have the problem that Ubuntu live CD has, namely, trying to auto-mount the now-unmountable partition (sda1), failing, and just sitting there, in the process keeping sda1 "busy" and not accessible to e2fsck.

I wanted to try that, but could not burn a good CD (i.e., one, booting from which would be fully successful without I/O errors), presumably because the CD writer I was using wasn't good enough for the "troubled" computer's CD drive to fully read.

I wondered if I could just change the startup options for Ubuntu live CD (this is how: https://help.ubuntu.com/community/BootOptions ) to tell Ubuntu, "please, don't touch /sda1 for now!" But adding options such as "sda=noprobe" (or should it have been "sda1=noprobe"?) to the boot command line seemed to have no effect whatsoever.

So I ended up using the alternative solution described at http://sanjayak71.blogspot.com/2010/...tion-from.html : basically, copying the entire /dev/sda1 to a huge disk file on another hard drive using the "dd" command, then running e2fsck on that file, and finally copying the "fixed" file back /dev/sda1 with "dd":

  #-- mount my other (good) hard disk drive
  sudo mkdir /mnt/b
  sudo mount /dev/hdb1 /mnt/b
  #-- copy 
  sudo dd if=/dev/sda1 of=/mnt/b/sda1.img
  #-- fix
  sudo e2fsck -y /mnt/b/sda1.img
  #-- once e2fsck completes successfully, move the data back
  sudo dd if=/mnt/b/sda1.img of=/dev/sda1

Even before moving the data back (the second "dd") one could temporarily mount the "fixed" file as a "loop mount" filesystem:

  sudo mkdir /mnt/loopa
  sudo mount -o loop /mnt/b/sda1.img /mnt/loopa

in order to verify that the "fixed" file system would indeed have your files as you know them. (I would, however, undo this temporary mounting (with "sudo umount /mnt/loopa") before doing the second "dd", to ensure I am not trying to copy a file system in an inconsistent state.

In Sanjay's post referred to above, he was, I think, using an external USB device instead of a second hard drive. But that wasn't an option for me, since all my external USB devices happened to be formatted with vfat, and could not create a fiel bigger than 4 GB.

In any event, this was a rather inefficient way for solving the problem (as compared to running e2fsck directly on the affected drive, if you could make it run!), since the rate of data transfer between drives with "dd" was under 0.5 gigabyte per minute on my machine, and for an entire partition that totals up to quite a bit of wait. But at least it worked.

Glad to see my solution has helped you. Of course this is when you don't have any other option.

[nutsy.ben]

Well. Got the same problem.

My workaround was to remove the hard drive and plug it as a slave into an external computer. then switch it off and replug the hard drive in the first computer.

Would be happy if there is a solution working faster.

[Supergamesoftoday]

I followed what you did, seeing as I have been having the same error messages as evryone else. I downloaded and successfully booted up Slax off of LiveUSB. However, I get this message:

e2fsck -y -f -v /dev/sda1
e2fsck: Bad magic number in super-block while trying to open /dev/sda1
/dev/sda1: 
The superblock could not be read or does not describe a correct ext2
filesystem. If the device is valid and it really contains an ext2
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
e2fsck -b 8193 <device>

Per the request, I tried e2fsck -b 8193:

e2fsck -b 8193 /dev/sda1
e2fsck: Bad magic number in super-block while trying to open /dev/sda1
/dev/sda1: 
The superblock could not be read or does not describe a correct ext2
filesystem. If the device is valid and it really contains an ext2
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
e2fsck -b 8193 <device>

I have also tried e2fsck -p /dev/sda1 and have received the same result. My Ubuntu install is 10.04LTS and so it has ext4. Not sure if I'm supposed to specify somewhere that it is.

Help!!

[Lrpbpb]

Supergamesoftoday, you ran e2fsck in /dev/sda1, but are you sure that is the correct drive?

Only asking because in my case I had a similar error, but it was because slax recognized my drive as "hda" instead of "sda" (like in ubuntu).

To know what drive is the right one, run:

fdisk -l

This will give you a list of your drives and partitions. Check and make sure you are using the correct partition on the correct drive.

If it is the right drive, it could be a bad superblock, as it says in your prompt. Try running (e2)fsck with another alternate superblock.

To find the backup superblocks run:

dumpe2fs /dev/sda"X" | grep -i superblock

Now you can use the backup superblock to check the filesystem using superblock #"X" (warning do not run the following on mounted live file system):

e2fsck -f -b "#" /dev/sda"X"

Replace "#" with the superblock numer, and sda"X" with correct partition.
Source: http://www.cyberciti.biz/faq/linux-f...e-superblocks/

Tell me if that solves the problem.

[Supergamesoftoday]

I am a moron.

You, sir/(madam?), are a genius. How bitingly obvious it was! fdisk -l indeed revealed the true path of my hard drive (/dev/hda1....not sda1), and I am now up and running as miraculously as the other success stories here.

For those that are interested, the reason I was using sda was because I had looked it up using disk utility in an Ubuntu Live CD, and I was indeed looking at my 38GB Linux partition, but apparently the naming convention must be slightly different.

I've been on Ubuntu for almost 3 full years now, and today I remembered why I joined Ubuntu. I love the fact that I can go to a thread that's several days old and get a response in under 24 hours. The Ubuntu community is the best in the world. It really leaves no reason NOT to go Ubuntu. You just don't get this kind of support anywhere else.

Thank you, Lrpbpb, and God Bless.

[xcorpion]

hi
i just step in
i m having a problem with my hp compaq cq41-208au
i was using win7 and then i install ubuntu 10.10 via internet.
after installing ubuntu it asks me for update and i accept it buh after it also ask me smthng grub and didnt notice what it says and just click restart
after i got a screen which says
error : no such device : bed4e5bc-7d2e-486e-a365-14e5de8d236c
grub rescue>

<Note: i have two partitions sda1 sda2 both are HPFS/NTFS
and my win7 is install in sda1 and ubuntu in sda2 and sda1 is boot*

help me out plz

[skpacman]

tried from slax, worked perfectly! good thing i have several flash drives to just throw stuff on!

[aslam]

I have same problem. My ubuntu 10.10 ext4 partition is broken while updating (kernel update)
sudo fsck /dev/sda6
fsck from util-linux-ng 2.17.2
e2fsck 1.41.12 (17-May-2010)
fsck.ext4: Device or resource busy while trying to open /dev/sda6
Filesystem mounted or opened exclusively by another program?

I tried Slax but not for me Slax does not support ext4 filesystem

Now downloading pmagic 5.9 i got it from another howto. It says supports ext4. I will try that will reply later

[aslam]

Parted Magic did the trick for me. Successfully recovered ubuntu 10.10 using gparted within parted magic
Here is the link for parted magic http://partedmagic.com/doku.php?id=downloads

[renderhead]

Solved - had similar issues with my Ubuntu 10.10 install. After an update (which appeared to go just fine) and reboot, arrived at the desktop - then system froze. I did a hard reset after a minute or two, and then same story as above - dropped straight to busybox. Ubuntu system partition 'busy' thanks to over-zealous automounting of unclean fs, fsck a no-go. Same automount hassles with LiveCD, tried Slax Remix (Slax doesn't support EXT4) - no fsck joy (same 'busy' message, though partition was not mounted - I assume same automount issue).

Finally tried sanjayak's creative solution (http://sanjayak71.blogspot.com/2010/...tion-from.html) using Ubuntu LiveCD (thanks to vmenkov for the link) with an external SATA HDD, and now everything is back and working just fine.

Thank you sanjayak! A seemingly extreme solution, but the only one I could get working.