VMS Help V73 Features, System Management Features, New System Parameters, WBM_MSG_UPPER  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    WBM_MSG_UPPER is one of three system parameters that are
    available for managing the update traffic between a master write
    bitmap and its corresponding local write bitmaps in an OpenVMS
    Cluster system. (Write bitmaps are used by the volume shadowing
    software for minicopy operations.) The others are WBM_MSG_INT
    and WBM_MSG_LOWER. These parameters set the interval at which the
    frequency of sending messages is tested and also set an upper and
    lower threshold that determine whether the messages are grouped
    into one SCS message or are sent one by one.

    WBM_MSG_UPPER is the upper threshold for the number of messages
    sent during the test interval that initiates buffered-message
    mode. In buffered-message mode, the messages are collected for a
    specified interval and then sent in one SCS message.

    The minimum value of WBM_MSG_UPPER is 0 messages per interval.
    The maximum value is -1, which corresponds to the maximum
    positive value that a longword can represent. The default is
    100.

    WBM_MSG_UPPER is a DYNAMIC parameter.