Proxmox
I was in the situation to install Proxmox on a second hand HP DL380 Gen8 Server with a P420i RAID controller.
Since Proxmox supports installation to ZFS out of the box I wanted to make use of that. Unfortunately with the somewhat older hardware there were a few hiccups I ran into. Hopefully with this blog entry I can help some people to save time and get their system up and running a bit faster than I did.