@gnomon Also, the current root disks are 500 GB NVMe drives, it's just that almost all of their space is in a ZFS pool. I sort of cut my 'how small can I make the root filesystem in order to have as much fast ZFS as possible' a little bit too close when I did this in (checks notes) late 2019[1].
1: https://utcc.utoronto.ca/~cks/space/blog/tech/MultiNVMeMotherboardIssue (blogging nearly everything can be helpful!)