Group_Size=interval
    Nogroup_Size

    Specifies the frequency at which XOR recovery blocks are written
    to tape. The group size can vary from 0 to 100. Specifying a
    group size of zero or specifying the Nogroup_Size qualifier
    results in no XOR recovery blocks being written. The Group_Size
    qualifier is only applicable to tape, and its default value is
    10. RMU Backup returns an error message if this qualifier is used
    and the target device is not a tape device.