A virtual disk back end can be exported multiple times either through the same or different virtual disk servers. Each exported instance of the virtual disk back end can then be assigned to either the same or different guest domains.
When a virtual disk back end is exported multiple times, it should not be exported with the exclusive (excl) option. Specifying the excl option will only allow exporting the back end once. The back end can be safely exported multiple times as a read-only device with the ro option.