You can use this option to turn the journaling of the disk on or off.
If journaling is turned on for a disk, OS X maintains a permanent record of changes made to files on the disk. If your computer stops because of a power failure or some other issue, OS X uses the journal to restore the hard disk to the last acceptable state before it was stopped.
Note: If journaling is turned off, it's not possible to verify the structure of the system files on the startup volume.