The EXT4 file-system today deprecated its journaled mode of the “data=journal” mount option. Following its deprecation, this mode is planned for removal in the year 2028.
The data=journal mode for EXT4 is where all file data and metadata is written to the file-system’s journal before being committed to the main file-system. In the event of a crash or power loss, the journal can then be replayed to recover the data.
The EXT4 data=journal mode is great for those very concerned about data integrity and safety but comes with significant hits to the write performance compared to the default ordered (data=ordered) mode or data=writeback. Using the journaled mode also disables delayed allocation and Direct I/O support.
EXT4 journal deprecated
Per today’s Git merge for Linux 7.3, the EXT4 data=journal feature is deprecated and support for it will be removed in early 2028 following the 2027 Linux LTS kernel version.
If you are using data=journal, as I was, the move to ordered requires that you have a battery backup that communicates with the system(s) it backs up.
Apc makes them and the apc kernel module works with them and is very well documented.
Two years to purchase and implement power failover and shutdown is plenty of time.
What reason is there to use EXT4 if not for the journal?
Just use F2FS or BTRFS at that point. (or ZFS if you’re fine with out-of-tree)
Wasn’t the journal the main selling point in the transition from EXT2 to EXT3? This seems kinda backwards, what even is the rational?
