OpenZFS's License

OpenZFS is a project to implement the Zettabyte FileSystem in an open source repo. It has modules to work on Linux funded by the Lawrence Livermore National Laboratory .

I still don’t really get the whole license debacle though. I know that the CDDL license it has is not fully GPLv2 compatible, so it can’t be integrated into the Linux kernel - but it’s still a free software license, it’s approved by both the OSI and the FSF.

I’ve heard it’s just potential legal incompatibilities and it’s not even a certain thing. I’ve also heard it gives Oracle full control of the project, making them some kind of puppetmaster from the shadows that could pull the rug at any time.

Is it really that bad? I’ve read the terms, I personally dislike weak copyleft licenses, but I can get why such a project chose it. It doesn’t really seem “unsafe” to me, just different.

It’s not that bad, and given that ZFS is a great piece of software, I think it’s worth using regardless of the slight incompatibility.


I guess you mean revoking the license, which for public licensing sounds seriously unrealistic. CDDL doesn’t explicitly forbids revocation (like most licences tend to have) but it does have this clause which seems rather similar:

And so far from what I’ve grasped of the license incompatibility, it means you can’t distribute them both at the same product (so can’t be mainlined), but as a separated package that users would install it seems fine (which is what Ubuntu, Alpine, … are doing).

After all it’s also the level of separation you’d need for other third-party modules with GPLv2-incompatible licensing like VirtualBox modules (GPLv3 and GPLv2 being incompatible with each others[1]), but also full-on proprietary ones like the nvidia drivers.

  1. Frequently Asked Questions about the GNU Licenses - GNU Project - Free Software Foundation ↩︎