Comment by agapon

Great blog post! Something from personal experience. OpenZFS on FreeBSD feels mostly like a port of illumos ZFS where most of the non-FreeBSD-specific changes happen in illumos and then get ported downstream. On the other hand, OpenZFS on Linux feels like a fork. There is certainly a stream of changes from illumos, but there's a rather non-trivial amount of changes to the core code that happen in ZoL.