The Dispatcher module found in Imagen package is used to perform remote script execution and load-balancing on a cluster of servers running Imagen. This provides good performance and scalability for enterprise-level systems based on Imagen. The Dispatcher uses weighted round-robin load-balancing algorithm to distribute the load among the servers. If any of the servers is not available, Dispatcher automatically employs another server from the cluster to process the request, thus eliminating a single point of failure.

The following diagram shows the boost in performance experienced when running this simple script  on a farm of one, two and three servers in a cluster. It displays the time (and respectively the number of generated images per second) for loading a page containing 29 images generated by this script. To get true results, we disabled Imagen cache. For this test we have used dual PIII/500Mhz machines with 256MB RAM and DMA/66 EIDE 40GB HDD.

Check out our configuration manual on how to setup Dispatcher on your servers, or use our installation services. We also provide ready-to-use cluster of high performance Imagen servers, where you can host your scripts.