changing an ext2 to an ext3 filesystem

The ext3 filesystem is an extension to the ext2 filesystem, and provides journalling. This has the advantage that often the filesystem does not have to be checked for consistency after a crash. Undeleting files is very difficult on an ext3 filesystem, however.

To convert an existing ext2 filesystem to an ext3 one:

tune2fs -j /dev/hda4

(replace /dev/hda4 by the name of the partition you want to convert)

Make sure you also change the relevant line in your /etc/fstab (replace the ext2 in the 3rd column by ext3). To change the filesystem back to ext2, all you have to do is change this entry in /etc/fstab back to ext2.