In this book we migrate both the data layer and business logic layer of a Scientific Workflow System to the Cloud. The migration scenario “Cloud Bursting” is considered. Several quantitative and qualitative metrics chosen from an ISO/ICE standard are introduced and are used to define the properties of the migrating methodologies. Two migrating methodologies are applied, one is the methodology of Bachmann, the other one is the methodology of Amazon. The required refactoring of the application architecture is investigated and the needed modifications are recorded and explained. Data of the metrics of the two migrating methodologies are collected, compared, and discussed.