why_not_both.jpg I have 2 NixOS-based NASes that run ZFS. each one has 3 equal-sized 256gb SSDs in addition to the pile o' spinning rust. each SSD has a small

why_not_both.jpg I have 2 NixOS-based NASes that run ZFS. each one has 3 equal-sized 256gb SSDs in addition to the pile o' spinning rust. each SSD has a small UEFI boot partition, then the rest of the space is cut in half. the root filesystem is a 3-way ZFS mirror of the first half of the SSDs. the second half of each SSD is another 3-way mirror, this time as the "special" / metadata device for the main hard-drive-backed zpool. any of the 3 SSDs can fail, and it will boot up and mount the storage perfectly fine. I could also easily upgrade to larger SSDs, in-place and with minimal downtime (zero downtime, if my case had hot-swappable SSD bays) it would work just as well with only 2 SSDs, but the incremental cost of a 3rd is small enough relative to the whole that I went for it.