mount: wrong fs type, bad option, bad superblock on /dev/sdb on CentOS 6.0

by Nic Young   Last Updated December 30, 2017 21:00 PM

Some how my partition on /dev/sdb has gotten all buggered up. This hard drive contains a lot of data that I need to recover and haven't been able to backup yet. WHen I attempt to mount it:

#mount -t ext4 /dev/sdb /world
mount: wrong fs type, bad option, bad superblock on /dev/sdb,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

Also when I run fdisk to try see what partitions are on the hard drive:

Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x25467742

   Device Boot      Start         End      Blocks   Id  System
/dev/sdb3   *           1           1           0    0  Empty
Partition 3 does not end on cylinder boundary.

I have attempted to use TestDisk to try to recover my lost partition but both quick and deep scans find no partitions present.

I am able to look at the used space and all of my data is still intact on the hard drive it self it just seems my partition is complete done. Is there any way I can recover this data? Any tools or details that I am missing? Thanks for your help in advance.


Output of my fstab file:

/dev/mapper/vg_atlasserver-lv_root /                       ext4    defaults        1 1
UUID=195465e0-00b6-49ad-9e81-2521316a808c /boot                   ext4    defaults        1 2
/dev/mapper/vg_atlasserver-lv_home /home                   ext4    defaults        1 2
/dev/mapper/vg_atlasserver-lv_swap swap                    swap    defaults        0 0
tmpfs                   /dev/shm                tmpfs   defaults        0 0
devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0
/dev/sdb                /world                  ext4    defaults        0 0

Answers 2

  1. Obviously you (should) mean "mount -t ext4 /dev/sdb1 /world"
  2. Make a 'dd' of your disk and work on that. The risk of hosing what's left is high
  3. Do you have a record of the previous partition layout? If so, you may try to recreate it. Remember to always mount readonly.


Alien Life Form
Alien Life Form
October 15, 2011 06:21 AM

An important point to note is that recreating your partitions does not actually affect the data stored on them; if you were to delete your partition table and recreate it _absolutely_exactly_, you should be able to mount the partitions that lived on it previously. The partition table is just instructions to the operating system about which blocks ought to contain various things (like the beginning of filesystems); if you ensure that there exists a partition table which makes the operating system look in the right place, then it should be able to find the filesystem.

It's also possible to edit your partition table by hand with a hex editor in lieu of recreating it from scratch. (I know the comic says FAT, it was really the partition table.)

October 15, 2011 08:03 AM

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