> ZFS is more efficient on FreeBSD (Insert Source)
FreeBSD and Linux share the same ZFS codebase, openzfs.
FreeBSD had its own zfs implementation but they had to drop it becayse they couldn't keep up with openzfs.
They merged with openzfs to maintain a common base so Linux didn't venture off on its own, not because they couldn't keep up.
But Linux makes it a faff because the license is incompatible so you have to run it as a 3rd party module and the kernel devs regularly break it. With FreeBSD it’s already there and you know it will work.
That's only partially true.
The license is "compatible" enough to be shipped by distributions rather than kernel.
AFAIK, the thing is: no one has seriously decided to test the license compatibility (as in, test it in court) and everybody's essentially scared of Oracle dragging them through endless legal litigation. Oracle owns most/all the IP that came from Sun Microsystems and while ZFS/OpenZFS is CDDL licensed... Who wants to spend millions in legal fees to find out?
Canonical did (still does?) ship OpenZFS with Ubuntu but maybe they're not big enough for Oracle to go after them (who knows? the lawnmower works in misterious ways).
My zfs never broke under Ubuntu and installation is easy by installing 1 package.
While they do share the same code base, personally (and therefore anecdotally) I have noticed an issue where on Linux with ZFS my programs will get OOM killed whereas they won't on FreeBSD+ZFS or on Linux+ext4. My theory was that the ARC pages on Linux weren't available for clearing under memory pressure whereas maybe they were in FreeBSD but that's just a guess. Hopefully someone knows more, but at least anecdotally even with the "same" ZFS code base, they can perform differently in situ.