I haven't yet tried a 5.0 installation, but I was wondering if the PVE installer allows creation of Linux software RAID and then installation of PVE on that RAID? On 4.x, I had to do a manual install of generic Debian first, then (hard to remember, it has been a few years ago) do something else to install PVE on top of that installation. I do remember at the time that this was *not* the recommended/supported way, although it worked fine and the server has been running flawlessly for several years. Alternatively, I could just install PVE on a single disk, create a RAID with another couple of disks, then keep the VMs and other important data on it.
for ZFS raid you can do all from installer.
you have option of ZFS raid-1 or ZFS raid-Z I think.
for mdadm raid you need to install Debian first as Debian installer lets you create mdadm raid during install and install on it.
but beware even though Debian installer let you create raid and install on it, only one of the disks are bootable.
you have to install grub on second disk manually after install.
at least that have been mine experience with it.
I think Proxmox ZFS install works better than that.
you have option of ZFS raid-1 or ZFS raid-Z I think.
for mdadm raid you need to install Debian first as Debian installer lets you create mdadm raid during install and install on it.
but beware even though Debian installer let you create raid and install on it, only one of the disks are bootable.
you have to install grub on second disk manually after install.
at least that have been mine experience with it.
I think Proxmox ZFS install works better than that.