An automated system and method is provided for system architects to model enterprise-wide architectures of information systems. From an initial model of a proposed system architecture, performance metrics are modeled and compared against a set of user-defined corporate and business requirements, including cost, quality of service and throughput. For unacceptable metrics, modifications to the system architecture are determined and proposed to the system architect. If accepted, the model of the system architecture is automatically modified and modeled again. Once the modeled performance metrics satisfy the corporate and business requirements, a detailed description of the system architecture derived from the model is output. The model of the system architecture also enables a business ephermeris or precalculated table cross referencing enterprise situation and remedy to be formed. A rules engine employs the business ephemeris and provides indications to the enterprise user for optimizing or modifying components of the enterprise system architecture.