The name of the storage area that will hold all segmented
    strings. You can only specify the SEGMENTED STRING STORAGE AREA
    clause in a multifile database. In a multifile database, if you
    do not explicitly define a storage area for segmented strings,
    they will be stored in the default storage area (RDB$SYSTEM).

    The page format for the segmented string storage area can
    be UNIFORM or MIXED. However, Rdb recommends that if you
    store segmented strings in a MIXED storage area, the storage
    area contain only segmented strings.