<h2>Specifies the journalling mode for file data. Metadata is always journaled. </h2>
All data is committed into the journal prior to being written into the main file system. This is the slowest variant with the highest data security.
All data is forced directly out to the main file system prior to its metadata being committed to the journal.
Data ordering is not preserved - data may be written into the main file system after its metadata has been committed to the journal. This is rumoured to be the highest-throughput option. It guarantees internal file system integrity, however it can allow old data to appear in files after a crash and journal recovery.