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