/sys$common/syshlp/helplib.hlb SET, AUDIT, Qualifiers, /BACKLOG  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /BACKLOG=[keyword[,...]]

    Specifies the thresholds for suspending a process that has
    exceeded the process message limit. The thresholds include the
    total number of messages in memory and the number belonging
    to the particular process. To prevent a process from being
    suspended, use the /EXCLUDE qualifier. Specify the following
    keywords:

    Keyword          Description

    TOTAL=(n1,n2,n3) Thresholds at which flow control is initiated
                     and accelerated; see description below.

    PROCESS=(p1,p2)  Thresholds at which process submissions are
                     controlled.

    Total             Process
    Messages Default  Messages Default Action Taken

    N1       100      P1       5       When there are 100 messages
                                       in memory, the audit server
                                       suspends any process that has
                                       submitted 5 or more messages
                                       until all messages are written
                                       to disk.

    N2       200      P2       2       When there are 200 messages
                                       in memory, the audit server
                                       suspends any process that has
                                       submitted 2 or more messages
                                       until all messages are written
                                       to disk.

    N3       300                       Any process with messages in
                                       memory is suspended until all
                                       messages are written to disk.