> Running ZFS on anything but Solaris/Illumos/FreeBSD is asinine.

> ZFS is a permanent second-class citizen on Linux

Linux is the primary target of OpenZFS [0] [1], and has been since 2020 [2]. It may not be supported by the Linux kernel developers, but it's supported by the ZFS developers, and that's all that really matters.

> I don't want to trust my data to some half-assed out-of-tree solution that may or may not break in a week.

Sure, it's an out-of-tree module, but that doesn't mean that it will randomly break all the time; it just means that you may occasionally need to wait for a new OpenZFS release before upgrading your kernel.

> FreeBSD ZFS support has matured and is outstanding.

Agreed, but Linux and FreeBSD both use the same ZFS [3], so I don't really see how the ZFS in FreeBSD can be better than the one in Linux. The tooling and install procedure is certainly better on FreeBSD, but the actual filesystem code is the same (and is probably slightly more robust on Linux since that's going to be where most of the testing occurs).

[0]: https://github.com/openzfs/zfs#supported-kernels-and-distrib...

[1]: https://github.com/openzfs/zfs/pull/8987

[2]: https://github.com/openzfs/zfs/releases/tag/zfs-2.0.0

[3]: https://docs.freebsd.org/en/books/handbook/zfs/