How to find fs corrupt or not & how torecover it

kishorelinux · 12-05-2013, 02:17 AM

hi friends,
i am new to linux. and my question is how can we find the file system is corrupt or not, an how we recover it.

And is this same for RHEL 6 & RHEL 5

Thanks for consider

kishore BANGLORE

gdejonge · 12-05-2013, 03:21 AM

The program you are looking for is called fsck.

The normal process is unmount the filesystem you want to check. Run fsck on the correct device and after that mount the filesystem again.

EXAMPLE

Code:

umount /dev/sdd1
fsck /dev/sdd1
mount /dev/sdd1 /mountpoint

If you need to check your root filesystem use a live-cd to boot your system.

As about recovering:
If the problems are not to severe, fsck can probably correct them for you. Otherwise you get your backup out and restore your data from there.

kapilbajpai88 · 12-05-2013, 04:35 AM

As suggested by Gerrard, the best idea is to boot from a live CD, if the failure is confirmed. General live CDs like Knoppix tend to come with a lot of data recovery tools, but there are also smaller CDs designed specifically for the task, such as SystemRescueCD. Once booted, you’ll find a range of options. If you’re particularly paranoid about your data, you can mount the damaged Filesystem in read-only mode and copy as many files as you can from it on to other local drives or across a network.

Another step to try before any Filesystem repair tools is a block scan of the hard drive. You can skip this if you’re sure the drive is fine, because it will take a while to run, but it doesn’t hurt to play it safe. Use the ‘badblocks’ command to run the block scan:
sudo badblocks -sv /dev/sdc

If you’re still not sure, run ‘dmesg’ in another console and look for I/O errors.