Thanks Justin.

Yes, I do know what RAID 0 is, but I prefer JBOD + incremental Time Machine back-ups + occasional SuperDuper mountable disk image back-up of my system drive, frozen in a working state and kept offline.

So now my question is why you need a server. Why not just network your machines like mlange is doing?

mlange, got it - archival. I'm not running a commercial facility, so that's not an issue for me; I have everything I've done in the last 20-odd years archived on my main machine.