I think the best approach here is to run the DNE-on-ZFS testing a few times to see which test scripts are passing regularly, and then move the passing scripts (or passing with minimal additions to ALWAYS_EXCEPT) to review-zfs-part-1 running with 4 MDTs and leave the failing tests (if not too many) in review-zfs-part-2 running with 1 MDT until we can fix the remaining test issues. As tests pass they can be moved into review-zfs-part-1 until it gets too large, and then just add the remaining few tests to ALWAYS_EXCEPT and set review-zfs-part-2 to also run with 4 MDTs and rebalance the tests to run with approximately the same time.

That way we can start basic DNE-on-ZFS testing ASAP and migrate the remaining ZFS tests to DNE without having to skip many of the tests.

Of course, if DNE-on-ZFS is mostly or completely passing today then this incremental migration to DNE testing can be skipped.