Abstract: An expert system methodology for operating a computer system is disclosed to facilitate tuning, that is, resource balancing of the various resources comprising a large-scale software system. The computer system is adapted to store a knowledge base derived from experts who manually tune the large-scale system. The system also stores site-specific information and specifications on components configuring the large-scale system. Performance measurements collected from the large-scale system on a time consistent basis are merged, utilizing the knowledge base, with reference data derived from the site-specific information and the specifications. As a result of the merger, the status of the large-scale system is classified as to its operability. If the status is in a predefined class requiring tuning, the computer system is arranged to generate programming code which will effectuate the required changes in the resources to thereby reconfigure the large-scale system.