- connect 4TB A and backup VMs to 4TB A
 - remove all disks, connect 4TB B and install proxmox on 4TB B
 - connect 4TB A and restore VMs to 4TB B
 - format 4TB A and add it in RAID 1 to 4TB B
 
Post install
NIC passthrough
I'm using a VM for pfSense, so we have to pass through the NIC to the VM. https://pve.proxmox.com/wiki/Pci_passthrough (opens in a new tab)
I think the dell motherboard needed intel_iommu=on outside the quotes at the end of the first line of /etc/kernel/cmdline
Storage not found
There may be an error that Proxmox is looking for the install ISO that was used to create the VM. In my case, I commented out the line in /etc/pve/qemu-server/{VMid}.conf and everything worked fine from there