I would rather it NOT become GPL as the GPL is a restrictive license. Leave it as BSD or even Apache.

ZFS on Linux and ZFS on Freenas both support feature flags, the problem has been that various new flags have rolled out from different vendors at different times and it’s taken a long time to reach parity between ZoL, Illumos and FreeBSD and it’s vary easy to create a pool on one system that can’t be imported on a system that doesn’t yet support the flags used by the pool. Of course you can always make a pool as an ‘older’ version but it requires effort and care. FreeBSD and ZoL can still import old Solaris 10 zpools, as long as they weren’t upgraded to a newer Oracle ZFS version post openzfs split for example.
The general goal now from what I understand is to unify the BSD and ZoL codebase into a singular unit reducing the problem and adding tools to make it easier to create portable pools.

Clearly somebody doesn’t know what open-source is. Patent issues could be fixed by filing with OIN. Code base has changed enough (over 50%) that I’m pretty sure they could have their own patent now. That or somehow convince evil Oracle to put the patent for ZFS currently under CDDL license under OIN. But Oracle won’t because that isn’t the type company they are. Microsoft did for everything and no one saw that coming so who knows? But Oracle continues to be a beast that needs to be put down.

FreeNAS doesn’t do any ZFS development. FreeBSD might have some feature flags that aren’t yet upstream. Both FeeeBSD and ZoL submit code upstream to OpenZFS.
Recently the FreeBSD guys announced they will be rebasing their efforts treating ZoL as upstream because that’s where the majority of ZFS development is these days.

CDDL provides patent protections that evaporate if the license starts to change. All the code that’s been replaced has been replaced with CDDL code. The project won’t switch licenses.

You’ve got no clue what yo are talking about, do you…..

Highly unlikely, unless someone criminally releases the code.
Stop stealing other’s work, create your own file system.

Both FreeBSD and Linux ZFS implementations originate from and share majority code of OpenZFS which is part of illumos. Both develop they own features hidden behind feature flags but work on integrating them in reference illumos implementation.

I’m no ZFS expert. But as I understand it any incompatibility has to do with available versions. FreeBSD tends to use a more recent version of ZFS which can have features that are incompatible with the Linux version.
That said as long as the the applications make the same calls to ZFS same the incompatibilities are not visible.

No they do not. It is an entirely different development branch, however, they try to remain comparable with freeBSD’s openzfs. To my knoledge, FreeNAS does not add anything to OpenZFS.
Im curious why ZOL (“ZFS on Linux”) was left out of this explanation when the purpose of the article is to differentiate between the different ‘common’ ZFS branches. ZFS on Linux is plenty popular to add to the discussion and is also fully supported on Ubuntu Linux (though it can be installed on any popular distribution such as CentOS, Debian, Arch).
In short, Ive used ZOL for a very long time and have only recently switched to FreeBSD (not FreeNAS) full time and I am noticing zero difference (my configuration is not that complex). They both just work.