Repairing Linux ext2 or ext3 file system

Posted by Vivek Gite [Last updated: October 27, 2006]

1) File system must be unmounted, you cannot repair it while it is running. Take system down to runlevel one (make sure you run all command as root user):
# init 1

2)Unmount file system, for example if it is /home (/dev/sda3) file system then type command:
# umount /home
OR
# umount /dev/sda3

3) Now run fsck on the partition:
# fsck /dev/sda3

However be sure to specify the file system type using -t option. Recenly one of our sys admin run the command on ext3 file system w/o specifying file system. Result was more corruption as fsck by default assumes ext2 file system.
# fsck -t ext3 /dev/sda3
OR
# fsck.ext3 /dev/sda3

Tip if you don't know your file system type then typing mount command will display file system type.

fsck will check the file system and ask which problems should be fixed or corrected. If you don't wanna type y every time then you can use pass -y option to fsck.
# fsck -y /dev/sda3

Please not if any files are recovered then they are placed in /home/lost+found directory by fsck command.

4) Once fsck finished, remount the file system:
# mount /home

5) Go to multiuser mode
# init 3

Read man page of fsck for more information. Make sure you replace /dev/sda3 with your actual device name.

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Discussion on This Article:

Anonymous Says: October 17th, 2005 at 2:20 am
simple and effective good pice of work
Anonymous Says: October 17th, 2005 at 7:50 pm
can I try same commands on HP/UX?
LinuxTitli Says: October 18th, 2005 at 12:32 am
Commands are same but syntax changes.

To repair HFS file system (/home)

umount /home
fsck –F hfs /dev/vg00/lvo1
mount /home

To repair JFS file system (/home)
umount /home
fsck –F vxfs /dev/vg00/lvo14
mount /home

Replace /dev/XXX/YYY with actual device file.
Anonymous Says: October 18th, 2005 at 11:25 pm
thanks for HP/UX JFS repair commands
General Zod Says: October 27th, 2006 at 5:16 pm
Concise, very effecive and to the point. Just what was required.
General Zod Says: October 27th, 2006 at 5:17 pm
excllent work
Jm Says: December 4th, 2006 at 3:05 am
What about to recover data that are deleted?
Thanks anyway…

http://linux-tweaks.blogspot.com
Lusidvicel Says: December 18th, 2006 at 5:50 pm
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Owain Says: March 3rd, 2007 at 10:03 pm
Thankyou - this page saved my life! (well, not literally). After checking loads of links that just told me what it said in the man page, here was a quick, easy and practical way to use the command.
jack Says: June 10th, 2007 at 4:50 pm
How do you check the / partition - which cannot be unmounted since it still shows as “in use” after going to run level 1? Is there a way without rebooting?
Paolo Says: July 14th, 2008 at 12:38 pm
Thanks, very good guide!