/sys$common/syshlp/helplib.hlb SCA, SCA Topics, Reducing LOAD Time  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    There are different means you can use to try to decrease LOAD
    time. Listed below are a few guidelines that may help you reduce
    LOAD time:

    o  Loading an SCA library for a software system is a time
       consuming operation and should be done in batch. Loading
       more than one module at a time is more efficient than loading
       modules separately. Using LOAD *.ANA is a common method for
       loading multiple modules. You use LOAD/DELETE to clean up .ANA
       files after they are loaded successfully and to use a little
       less disk space during the load.

    o  With large software systems, it is a good idea to use more
       than one SCA library and load them all simultaneously. This
       can lessen the elapsed LOAD time considerably. You should be
       able to load several libraries simultaneously on a single
       disk. Additionally, using more than one CPU to do your loads
       also helps, but SCA loading is mainly I/O intensive. For more
       information about how to use multiple libraries, see the help
       subtopics under Libraries.

    o  Once your SCA library starts getting above 20K blocks, you
       should consider preallocating the library when you create it.
       SCA currently extends the library file by 1000 blocks at a
       time, so for large libraries it frequently extends the library.

       You can preallocate an SCA library by specifying CREATE LIBRARY
       /SIZE=xxx, where xxx is the size of the library in disk blocks.

       Use the size of the SCA$EVENT.DAT file in your current SCA
       library directory as the value to the /SIZE qualifier.

    o  SCA uses a large number of I/Os during LOAD. Loading an SCA
       library on a heavily used or badly fragmented disk causes the
       load to be less efficient.

       You can tell how badly your SCA libraries are fragmented by
       using the following command:

         $ DUMP/HEADER/BLOCK=COUNT=0 -
         _$ DISK:[sca_library_directory]SCA$EVENT.DAT

       The interesting portion of the output is the Map area. Each
       retrieval pointer represents a contiguous section on the disk.
       Because SCA extends SCA libraries 1000 blocks at a time, having
       a lot of retrieval pointers smaller than this is a strong
       indication that some defragmentation is needed.