Journaling is the recording of the file system with all changes in a log file. The entries are made before the file system is changed, which means that the consistency of a file system can be restored after a system crash by reading out the log file.
There are file systems that work without journaling and for which the recovery procedure takes a corresponding amount of time. Journaling ensures the consistency of the file system, even in the event of a system crash. In the case of distributed file systems, journaling is only used for the Global File System (GFS), a license-free cluster file system.