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EXT4 Deprecates Its Journaled "data=journal" Mode (www.phoronix.com)
submitted 2 days ago by to c/linux@lemmy.ml
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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.

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[–] 3 points 2 days ago (8 children)

Wasn't the journal the main selling point in the transition from EXT2 to EXT3? This seems kinda backwards, what even is the rational?

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  • [–] 6 points 2 days ago (7 children)

    The metadata journal is still there. Most people are not journaling their data, it's too slow.

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  • [–] 1 point 2 days ago (6 children)

    Ah, I see! From googling "data=ordered" is the default and does what you said. Still, why not leave it for those that want it?

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  • [–] 3 points 2 days ago (5 children)

    Maintenance is not free? They still have to test it at the very least.

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  • [–] 2 points 2 days ago (4 children)

    Yeah, but I thought the philosophy was not to break userspace. I'm fine with the removal if absolutely nobody uses it, but some have commented here being users of the feature

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  • [–] 1 point 23 hours ago (2 children)

    I think its userspace too. But I don't know how this is defined anyway. Otherwise removing any drivers in the Kernel would count as breaking userspace too, and they do it all the time.

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  • [–] 1 point 22 hours ago (1 child)

    The removed drivers are usually those that are really old and not used by anybody (using the latest kernel), so it's a bit different.

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  • [–] 2 points 21 hours ago

    Sure, but I think the point is that most people don't even use data=journal option with EXT4. If I understand it right. But I get it, EXT4 is a common and stable and important part of Linux. Removing any feature, even if it not that many uses them, sounds wrong to me too. My previous point was actually trying to define if this falls into breaking userspace, and I just took a random example that affects userspace too. Because Linus doesn't say "we are only allowed to break userspace, if just a few people use it", he does not want do it at all. My point was, a driver in Kernel doesn't fall under userspace.

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