VMS Help LANCP, DEFINE, DEVICE, Qualifiers, /VOLATILE_DATABASE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Updates the device entries in the LAN permanent device database
    with any data currently set in the volatile database. This allows
    you to update the permanent database after changing data in the
    volatile database, rather than repeating the commands for each
    updated entry to apply the changes to the permanent database.