No you dont need to Deactivate the lun for creating a remote mirror : I think you are wanting to ask that do i need to Fracture a lun
Hi, Do I've to deactivate Lun before creating Remote Mirror when I'm creating for the first time that includes Lun Creation aswell. Can anyone provide any link or Doc to clear my doubts on replication concepts. 
Do I've to deactivate lun before creating Remote Mirror