Beginning with OpenVMS Version 8.2, the default values of NPAG_
    AGGRESSIVE and NPAG_GENTLE are 100. A value of 100 turns off
    both gentle and aggressive reclamation of nonpaged pool lookaside
    lists. In many cases, when pool reclamation moves small packets
    from the lookaside lists back to the variable list, the result
    is fragmentation of the variable list. This fragmentation appears
    as many small packets at the front of the variable list and a few
    large packets at the end of the list.

    When an allocation occurs for a packet that is larger than any
    of the lookaside lists, the system must find a large enough
    packet on the variable list. When heavily fragmented, the entire
    variable list often must be searched to find a large enough
    packet. Because the variable list is kept in address order, when
    a large packet is deallocated, the entire list must be searched
    again to deallocate the packet.

    Under these conditions, system performance can be severely
    degraded. For this reason, VSI recommends that you turn off pool
    reclamation but keep both NPAG_AGGRESSIVE and NPAG_GENTLE system
    parameters set to 100.

    NPAG_AGGRESSIVE is a DYNAMIC parameter.