A normal hot spare will have a single bound LUN which consumes the entire disk. That LUN is where the data is copied to when a disk failure occurs. As long as the Disk is in a 1-disk Hot Spare RAID Group, and has a Hot Spare type LUN bound, it should work fine.  Richard J Anderson
  Hi All, I am looking for a procedure to rebuilt a hot spare disk. For some apparent reason our hot spare disks are full but there is no fault with any disks in the array.      
Hot spare rebuilt