After a few hours I've been unable to get Metricbeat to read ZFS stats.
It looks like GitHub - maireanu/zfsbeat has gone stale as the last work was 2 years ago.
Seeing as ZFS is nodev in
/proc/filesystems the default fsstat module in metricbeat is unable to read it. Is their an easy way to see remain space. It would be nice to see the overall health like the above reference but it fails to build.