Active_IO=max-reads

    Specifies the maximum number of read operations from a backup
    device that the RMU Dump After_Journal command will attempt
    simultaneously. This is not the maximum number of read operations
    in progress; that value is the product of active system I/O
    operations.

    The value of the
    Active_IO qualifier can range from 1 to 5. The default value
    is 3. Values larger than 3 can improve performance with some tape
    drives.