Apache MPM os2
Summary
    The Server consists of a main, parent process and a small, static
    number of child processes.
    The parent process's job is to manage the child processes. This
    involves spawning children as required to ensure there are always
    StartServers processes
    accepting connections.
    
    Each child process consists of a a pool of worker threads and a
    main thread that accepts connections and passes them to the workers via
    a work queue. The worker thread pool is dynamic, managed by a
    maintenance thread so that the number of idle threads is kept between
    MinSpareThreads and
    MaxSpareThreads.