Our society increasingly depends on computer-based systems; the number of applications deployed has increased dramatically in recent years and this trend is accelerating. Many of these applications are expected to provide their services continuously. The Service Availability Forum has recognized this need and developed a set of specifications to help software designers and developers to focus on the value added function of applications, leaving the availability management functions for the middleware. A practical and informative reference for the Service Availability Forum specifications, this book gives a cohesive explanation of the founding principles, motivation behind the design of the specifications, and the solutions, usage scenarios and limitations that a final system may have. Avoiding complex mathematical explanations, the book takes a pragmatic approach by discussing issues that are as close as possible to the daily software design/development by practitioners, and yet at a level that still takes in the overall picture. As a result, practitioners will be able to use the specifications as intended. * Takes a practical approach, giving guidance on the use of the specifications to explain the architecture, redundancy models and dependencies of the Service Availability (SA) Forum services * Explains how service availability provides fault tolerance at the service level * Clarifies how the SA Forum solution is supported by open source implementations of the middleware * Includes fragments of code, simple example and use cases to give readers a practical understanding of the topic * Provides a stepping stone for applications and system designers, developers and advanced students to help them understand and use the specifications