FreeBSD ZFS will be changing to be based on ZFS on Linux
The big news today is contained in an email thread called The future of ZFS in FreeBSD (via any number of places), where the crucial summary is:
[...] This state of affairs has led to a general agreement among the stakeholders that I have spoken to that it makes sense to rebase FreeBSD's ZFS on [ZFS on Linux]. [...]
This is not a development that I expected, to put it one way. Allan Jude had some commentary on OpenZFS in light of this that's worth reading for interested parties. There's also a discussion of this with useful information on lobse.rs, including this comment from Joshua M. Clulow mentioning that Illumos developers are likely to be working to upstream desirable ZFS on Linux changes.
(I had also not known that Delphix is apparently moving away from Illumos.)
I've used ZFS on Linux for a fairly long time now, and we settled on it for our next generation of fileservers, but all during that time I was under the vague impression that ZFS on Linux was the red-headed stepchild of ZFS implementations. Finding out that it's actually a significant source of active development is a bit of a surprise. On the one hand, it's a pleasant surprise, and it definitely helps me feel happy about our choice of ZFS on Linux. On the other hand it makes me feel a bit sad about Illumos, because upstream ZFS development in Illumos now appears to be yet another thing that is getting run over by the Linux juggernaut. Even for Linux people, that is not entirely good news.
(And, well, we're part of that Linux juggernaut, since we chose ZFS on Linux instead of OmniOS CE. For good reasons, sadly.)
On the other hand, if this leads to more feature commonality and features becoming available sooner in FreeBSD, Illumos, and ZFS on Linux, it will be a definite win. Even if it simply causes everyone to wind up with an up to date test suite with shared tests for common features that run regularly, that's probably a general win (and certainly a good thing).
(One thing that it may do in the short term is propagate FreeBSD's
support for ZFS sending
TRIM commands to disks into ZFS on Linux,
which would be useful for us in the long run.)
PS: The fundamental problem with ZFS on Linux remains that ZFS on Linux will almost certainly never be included in the Linux kernel. This means that it will always be a secondary filesystem on Linux. As a result I think it's not really a great thing if ZFS on Linux becomes the major source of ZFS development; the whole situation with Linux and ZFS is always going to be somewhat precarious, and things could always go wrong. It's simply healthier for ZFS overall if significant ZFS development continues on a Unix where ZFS is a first class citizen, ideally fully integrated into the kernel and fully supported.