xcp add disk

xe sr-list #gives you a list of sr’s from which to pick a sr-uuid

xe vdi-create sr-uuid= name-label= type=user virtual-size=
#the above vdi-create outputs a vdi-uuid

xe vm-list # gives you a list of vm’s from which to pick a vm-uuid

xe vbd-create vm-uuid= vdi-uuid= bootable=false mode=RW type=Disk device= #pick an unused device name (my box had “disks” up to xvdc so I used xvdd)
# the above vbd-create outputs the vbd’s uuid

xe vbd-plug uuid=
#your new devices should now be visible from your domU