We need to enable 32-bit project identifier support (PROJID32BIT feature) for our naming scheme (uid numbers larger than 65'536):
mkfs.xfs '''-i projid32bit=1''' /dev/vdb
=== Update fstab ===
/etc/fstab
/dev/vdb /var/backup xfs noatime,uquota,pquota 0 0
=== Mount ===