Journaled File Systems options

Journaled file systems write critical information about file system operations to a journal before actually modifying files. In the event of an unclean shutdown, the file system can be recovered more quickly by reading the journal instead of performing fsck. Journaling Options available in ext3

data=ordered - This is the default mode. Only meta data is journaled.
data=journaled - Meta data and data are journaled.
data=writeback - Not as good as “data=ordered”, but allows for a quicker fsck than standard ext2.

Converting from ext2 to ext3
Because of their close relation, it is fairly simple to upgrade from ext2 to ext3:
Modify file system type in /etc/fstab

Create the journal: tune2fs -j /dev/hda1

Make sure you fire mkinitrd command and create new initrd file for ext3 FS