(Previously)

With my server in place, I ran a memtest on it … which with 128G took a while ;)

And then installed Proxmox 4, using a bootable USB that I’d created on my Mac from the ISO downloaded from Proxmox’s website. To create the bootable USB, create the img file:

hdiutil convert -format UDRW -o target.img source.iso

and then burn it to USB:

sudo dd if=target.img of=/dev/rdiskN bs=1m

Replace N with the correct device based on diskutil list output. Don’t get it wrong, else you’ll properly knacker your machine :D