ZFS is an enterprise software RAID, and 1:1 RAM to TB is the minimum recommended requirement for a production server (e.g. enterprise implementations).

I’ve seen many users stating they have far far less than 1:1 without issues. I recall a r/DataHoarder user saying they have 100+ TB’s and only 16 or 32GB RAM, which is not fully utilized, so it all depends on your usage profile and the size/scale of r/w ops occurring during peak periods.