My old case was a big workstation one with 10 drive bays already. Definitely preferable to having them loose

I bought a plastic tower for disks which let's me have 10 disks with some space between them. I then bought some Artic fans and attached them with tape to the 'tower'. Then I used a 11 years old optiplex 990 as Debian zfs connected to 8 of the disks, and I have 2 spares which I'll be able to use when the others die.

Performance is great. I could do it because I was given those disks for free, with plenty of ours on each of them.