Modelling a computer based business process having a number of functional steps, involves providing software candidate models (740) of the business process, each specifying the functional steps (750), an arrangement of software application components (770) for carrying out the functional steps, and a design of computing infrastructure (780), for running the software application components, to meet given non functional requirements, and suitable for automated deployment. For each of the candidate models, operation of the business process is simulated (730) according to the respective candidate model and their simulated operation is evaluated against the non-functional requirements. The simulation can help the search for a suitable or optimum deployment to be more efficient and can lead to more efficient usage of shared resources.