Gearman4Perl and in general

Gearman - intro

 1. Start gearman `server` on some machine (here `worker` machine):
    $ gearmand  --port 8888
 2. Connect a `worker` to the server 
    $ gearman -h IP -p 8888 -w -f test wc  
    $ gearman -h 127.0.0.1 -p 8888 -w -f test executable_script
 3. Push a job to queue by calling:
    $ gearman -h IP -p 8888 -f test "SOME DATA TO PROCESS OR ARGS"

Notes:
   * Gearman does NOT spawn any `worker` processes, therefore if a number of `workers` 
      becomes exceeded the `client` has to wait to be served.
    * Gearmand debug-info problem none of --debug=1 or -vv options of gearmand seems to work
    * Gearmand server can go down and up without the need to re-attach workers to it 
    * If the `worker` crushes (or machine it runs on) there is the `client` that has to decide what 
      should be done 
    * If the `client` crushes then the way to manage that is: 
        - use a monitor service like launchd, or daemntools/supervise                                                                                                                                        
            http://cr.yp.to/daemontools/supervise.html
            http://launchd.macosforge.org/ AND http://developer.apple.com/macosx/launchd.html
        - run those `clients` periodically repeatable with check if completed in previous run 
    * `client` can't pass complex data structures to the `worker`.
      Passed data needs to be scalar or eventually a scalar reference. In case application 
      forces passing some input data structure the serialization will make it possible:
        - Text format:
            + at `client` JSON::XS::encode_json and than on `worker` JSON::XS::decode_json
        - Bin format:
            + at `client` Storable::nfreeze (for portable image) and than Storable::thaw on `worker`
      and then it can be passed as a scalar. Alternatively consider the possibility of getting the input
      data by the `worker` by itself. 

Additional info:
   * http://assets.en.oreilly.com/1/event/27/Gearman_%20Bringing%20the%20Power%20of%20Map_Reduce%20to%20Everyday%20Applications%20Presentation.pdf
   * http://www.slideshare.net/andy.sh/gearman-and-perl