/RVN=n
       /RVN=0 (default)

          When you have a bound volume set, use this qualifier
          to identify a disk from the volume set or all disks
          in the volume set. The default of zero tells the
          Disk File Optimizer to defragment all disks
          in the bound volume set. Specify a relative volume
          number (RVN) to defragment a specific disk that
          belongs to a bound volume set.