[AndrewDavis]

Together FreeBSD, ZoL and the Illumos groups work on OpenZFS.

Oracle closed off Solaris. The decendent of Open Solaris is Illumos. Oracle ZFS and OpenZFS are not hte same thing.

OpenZFS repo is the upstream, though it is closely tracks the Illumos version.

From there the projects pull on OpenZFS to create their implementations. New features are developed independently by the projects with rules that a new feature must be enabled in a downstream distro for X period of time before it can be upstreamed into OpenZFS.

[ryao]

Let's not forget Mac OS X and OSv, although the amount of work being done that and shared is not as large as it is with the other 3 platforms.