39 comment

1. Well written article with lots of good information.
   Does any of this work on OpenBSD and the ffs
   file system?

   1. if using mount command on BSD OSs (FreeBSD, FreeNAS, etc), you will always receive the error in the OP as it’s not the proper syntax.

      To mount ext2 on BSD OSs, the correct command would be:

      mount -t ext2fs /dev/YourDevice /mnt/YourMountPoint

      Please refer to the ext2fs man page:

      https://www.freebsd.org/cgi/man.cgi?format=html&query=ext2fs%285%29

2. thank you very much for the valuable inforamation

3. Lately I’ve noticed that when I Google on Linux questions, this site consistently returns the best or one of the best responses to what I was trying to solve. Because of that, I have signed up for your daily newsletter. Thanks for the great site!!

4. Very good information.

5. Awesome. Thanks.
   This is exactly what I needed instead of all the opinion with no solution.

6. Awesome. Worked Perfectly on RHEL5

7. Worked perfectly under RHEL5. Notes on my issue are below

   I was getting following error when mounting.
   Wrong fs type, bad option, bad superblock on /dev/sdd1
   missing codepage or other error
   In some cases usefull info is foinf in syslog – try
   dmesg | tail or so

   dmeg | tail displayed
   EXT3-fs: filesystem has both journal and inode journals!

   I tried useing the tune2fs -f -O ^has_journal /dev/sdd1 to remove the journal and try recreating but it did not work. tune2fs just hung there sucking 100% CPU when trying to remove the journal

   The command given here worked great.

8. Does not seem to work, when I run dumpefs all it says:

   “Bad magic number in super-block while trying to open…”

   I already know the superblock is bad.

9. Another way to cut to the quick of finding out where your superblocks should be after losing your primary is to use the following command:
   # mke2fs -n /dev/[device and partition number]
   This is making the utility you used to create the filesystem tell you where the backups are. You get a response similar to this:
   # mke2fs -n /dev/sdb1
mke2fs 1.39 (29-May-2006)
Filesystem label=
OS type: Linux
Block size=1024 (log=0)
Fragment size=1024 (log=0)
62248 inodes, 248976 blocks
12448 blocks (5.00%) reserved for the super user
First data block=1
Maximum filesystem blocks=67371008
31 block groups
8192 blocks per group, 8192 fragments per group
2008 inodes per group
Superblock backups stored on blocks:
8193, 24577, 40961, 57345, 73729, 204801, 221185

   Now, remember when using this command, you need to use the same flags you used when you created the filesystem originally, and just add ‘-n’ to them. If you made an ext3 filesystem, you would use:
   # mke2fs -j -n /dev/[device and partition number]

   HTH.

   1. Yes. Indeed this is a great shortcut – mke2fs -n /dev/XX .

      Thank you for suggesting this.

      This is a wonderful website with easy to understand and clear text linux resource. Simply, one of the best Linux learning sites on the net.

      1. Also you can use mkfs command, for example for ext4 fs:

         mkfs.ext4 -n /dev/XX

10. Hi, this looks like a potential lifesaver. Great Stuff. Question: do superblocks ever move?? Obviously i don’t know ext3 filesystem internals — too much to learn, so little time… My point is: would there be any value in storing the list of superblock locations offline?

    Thanks,
    Marty.

11. @uncle max

    You can.. but I strongly recommend backup instead of just superblocks. Linux comes with rsnapshot backup tool that can make hourly, daily and weekly backup of all your servers. If you are old school UNIX person, tar, dump and restore are regular tools for backup.

    HTH

12. thank you so much, this is valuable information, and it saved me a LOT of work!!!!!

    thanks for the write up, awesome, worked like a charm on ubuntu 9.10 off live cd rescuing a / partition on my HDD

13. Thank you! Successfully recovered my data, and with much less stress than I might have had due to the clear explanations. Thanks also to ShadowCat8 – I was getting magic error numbers with the other method of finding the superblock locations.

14. hi.. Even after i run d command i m gettin a ‘couldnt find ext2 superblock. Tryin backup blocks’ n then a bad magic number in superblock again! I ve lot of data n desperately need to retrieve them..

    Thanks,
    Ashwin

15. Good and simple.
    I believe we will be able to mount the fs using a diff super block “only” if we r running system in rescue mode with cd media mounted,
    I could not mount the fs when the system was live.. instead i was seeing help of mount command

    mount sb=”204801″ /dev/hda1 /vol1
    Usage: mount -V : print version
    mount -h : print this help
    mount : list mounted filesystems
    mount -l : idem, including volume labels
    So far the informational part. Next the mounting.
    The command is `mount [-t fstype] something somewhere’.
    Details found in /etc/fstab may be omitted.
    mount -a [-t|-O] … : mount all stuff from /etc/fstab
    mount device : mount device at the known place
    mount directory : mount known device here
    mount -t type dev dir : ordinary mount command
    Note that one does not really mount a device, one mounts
    a filesystem (of the given type) found on the device.
    One can also mount an already visible directory tree elsewhere:
    mount –bind olddir newdir
    or move a subtree:
    mount –move olddir newdir
    A device can be given by name, say /dev/hda1 or /dev/cdrom,
    or by label, using -L label or by uuid, using -U uuid .
    Other options: [-nfFrsvw] [-o options] [-p passwdfd].
    For many more details, say man 8 mount .

    any clues on this?

16. Awesome.

    Here is what I did that worked for me.

    $ dumpe2fs /dev/sda6
    – got just the “Bad magic number in super-block while trying to open…” message
    used
    $ mke2fs -n /dev/sda6
    got the 2nd super block same as in the example.
    Used:
    $ fsck -b 32768 /dev/sda6
    to fix.

    Should have used “-a” option to automatically accept fixes because it had a gazillion complaints and I had to lean on the “y” key for 20 minutes. My disk may not be optimally fixed, but I can see the data I was missing before which is a big step forward.

    Thanks,!

    I

17. Hi there!
    Sorry, I can’t find, here in this place, the example where was the explanation in how to recover a NTFS partition with linux utils; I remember I red, that the program asks if the partition was created under Vista.
    A friend of mine, needs back his HD, at least, recover his important data, I told him that it could be possible to restore the whole drive too.
    Thx!

18. Hi, I still have a problem. Have tried all things suggested in comments, still no luck, just get these errors

    freenas:/mnt# mke2fs /dev/ad1
    mke2fs 1.41.14 (22-Dec-2010)
    /dev/ad1: Operation not permitted while setting up superblock

    or

    dumpe2fs /dev/ad1
    dumpe2fs 1.41.14 (22-Dec-2010)
    dumpe2fs: Bad magic number in super-block while trying to open /dev/ad1
    Couldn’t find valid filesystem superblock.

    or

    fsck -t ufs /dev/ad1
    ** /dev/ad1 (NO WRITE)
    Cannot find file system superblock
    ioctl (GCINFO): Inappropriate ioctl for device
    fsck_ufs: /dev/ad1: can’t read disk label

    1. @Bryn

       You need to use the -n switch with fsck

19. nice really help me!! regards!

20. Great help thanks guys.. Only one issue.
    After getting super block issue fixed guess some fragmenting was conducted) I now continue to get the following message:

    Inconsistency detected by ld.so: dynamic-link.h: 187: elf_get_dynamic_info: Assertion `info[20]->d_un.d_val == 7′ failed!

    So far it’s whenever trying to run firefox, thunderbird, deluge or Virtual box.
    Tried removing and re-installing, still no luck. Any suggestions greatly appreciated.

21. Helped me when restoring from a bad superblock, kudos and hopefully a quick upvote on Google’s search rankings!

22. No rsaoen why you can’t run linux if your clients run windows… ;)Just saying there are a lot of good rsaoens to try it out ;)I can respect windows…MS makes life easy in some ways, but I know that after using Linux for 5 years I pull my hair out every time i have to diagnose a problem in windows, or get it to do some specific thing, etc.I don’t want everyone running linux, just enough to make MS improve the bits they are terrible at ;)

23. When you answer “yes” to the following question, might files be lost / deleted? (What if you answer “no” to the question?)

    Free blocks count wrong for group #368 (32254, counted=27774).
    Fix? yes

24. You can also use superblock stored at 32768 to mount partition, enter:
    # mount sb={alternative-superblock} /dev/device /mnt
    # mount sb=32768 /dev/sda2 /mnt

    should it not be?

    You can also use superblock stored at 32768 to mount partition, enter:
    # mount -o sb={alternative-superblock} /dev/device /mnt
    # mount -o sb=32768 /dev/sda2 /mnt

    tip: it using it on loop? pass -o loop,sb=32768
    else excellent and had to also RTFM man mkfs.ext3 and also cat /etc/mke2fs.conf

25. You saved me!!!! Thanks for the post!

26. Nice! saved me so i can a least backup and rebuild raid. thats if drive is not gone bad.
    cheers.

27. I just stumbled on this page and I would like to thank because I think it is really what I need :)

    I have a superblock read failure at boot time, I’m asked to type the root password and I managed to browse the root / partition, that was the only one that the system was able to mount. At this point I used fsck as explained above on the / partition and fixed hundreds of errors, but after the reboot the broken superblock situation is still present. Trying to reiterate restoring the superblock with fsck didn’t help.
    Do I have to fix the superblock of the other partition on my disk? Those partition are /home and /usr/local, which contains the important data and I would like to be sure that they are not accessible before modifying their superblock. Now I am not in front of my broken PC and unfortunately yesterday I didn’t try to mount the other partitions.
    So, how can I know which is the partition with a broken superblock? Is it safe trying to run fsck on an eventually clean pertition?
    In addition, I don’t understand how is it possible that I managed to browse the / partition if its superblock was broken.

    thanks in advance for any answer

28. It worked! Many thanks!

29. Is there any possibility to copy superblock to other identical drive??
    I had RAID1 setup which both drivers mechanically failed. I can mount another but another is missing superblock.
    Drives are identical so could there be someway to copy superblock from /dev/sda6 to /dev/sdb6 or should i try to mdadm –create command keep fingers crossed that it doesn’t destroy data.

30. Thanks for the nice article. In one of my Ubuntu machine, the boot stopped in initramfs, I booted with a liveUSB and found that the journal on the disk was corrupted. Running fsck repaired it. Thanks again for your help.

31. Hi every one i don’t know this is right forum or not but when i read about fsck and repair options i think any of expert from above will definitely help me. I am using LynxOS 2.XXX WITH SHIMADZU CT SCAN system and application .it’s uses LynxFS file system.while system in running state i have used mkfs command accidentally and now one of my partition is showing empty disk.So i tried recovery and found that no any recovery software can understand this partition style but i can successfully make image of this drive. and when for repair work finally i saw in RAW Display of partition which is /dev/sdob has data in raw format so i think due to mkfs is front end and high level tool this only changed my partition table and still data is there.I have 3 partitions Sd0a Sd0b Sd0c , a and c is ok and b having partition table issue Please help me if any one can? my mail : [email protected]

    regards
    Vikrant
    Mumbai – INDIA

32. Hi

    I have read all your suggestions given to the readers. I have accidently run fsck on a corrupted umounted file system without taking back up. As it is showing some data loss during fsck. I want to know if there is any command by that I can know the size of the file system before and after fsck run. So that I can confirm is there any data loss or not.

    Thanks in advance
    Satish Amrutwar

33. Hi !
    What do I do in the last line
    Cp file /path/to/safe/location ?
    Can someone give an example ?

34. You are a life saver man. This piece of blog is solid gold. Thanks

35. YOU SAVED ME !!!

    BIG THANKS

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