EXT4 Deprecates Its Journaled "data=journal" Mode
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.
https://www.phoronix.com/news/EXT4-Deprecates-Journal-Mode?=0Open linkView original on toast.ooo
6 replies
The plan is to stop journaling altogether? Isn’t that kind of a huge change, or am I missing something?
No. The ext4 default mode is ordered, not journaled. The metadata is still journaled though.
I don't see any discussion on the kernel mailing list, though I've never gone looking for anything in there before.
Sortof... but almost nobody is actually using
data=journal, as the default isordered.I do think it's important to keep it as an option though, so I disagree with removing it entirely. I suppose it could be forked into a separate module by someone who wants to maintain the journal support. I wonder if ext3's journaling will still be supported?
Sounds like a big one to me. But I think it's also fair to say ext4 isn't really good for journaled data storage, especially compared to the competitors.
Reading through the phoronix comments, its default mode journals file metadata only instead of all writes.
Can someone ELI5 it for me on what does this mean on a technical standpoint?