ext3 filesytem is a journal’d filesystem. The command “tune2fs“ can add a journal to an existing ext2 file system and convert it to ext3, without altering the data already on the partition.
To convert an ext2 file system to ext3, log in as root and type:
/sbin/tune2fs -j /dev/hdbX
In the above command, replace /dev/hdb with the device name and X with the partition number.