https://openzfsonosx.org/wiki/Main_Page
It was actually the NetApp lawsuit that caused problems for Apple’s adoption of ZFS. Apple wanted indemnification from Sun because of the lawsuit, Sun’s CEO did not sign the agreement before Oracle’s acquisition of Sun happened and Oracle had no interest in granting that, so the official Apple port was cancelled.
I heard this second hand years later from people who were insiders at Sun.
While third-party ports are great, they lack deep integration that first-party support would have brought (non-kludgy Time Machine which is technically fixed with APFS).
It was killed because Apple and Sun couldn't agree on a 'support contract'. From Jeff Bonwick, one of the co-creators ZFS:
>> Apple can currently just take the ZFS CDDL code and incorporate it (like they did with DTrace), but it may be that they wanted a "private license" from Sun (with appropriate technical support and indemnification), and the two entities couldn't come to mutually agreeable terms.
> I cannot disclose details, but that is the essence of it.
* https://archive.is/http://mail.opensolaris.org/pipermail/zfs...
Sun took DTrace, licensed via CDDL—just like ZFS—and put it into the kernel without issue. Of course a file system is much more central to an operating system, so they wanted much more of a CYA for that.
Naa it was Jobs ego not the license:
>>Only one person at Steve Jobs' company announces new products: Steve Jobs.
https://arstechnica.com/gadgets/2016/06/zfs-the-other-new-ap...
But I think these things are usually a combination. When a business relationship sours, agreements are suddenly much harder to work out. The negotiators are still people and they have feelings that will affect their decisionmaking.