Availability and disaster recovery represents a billion dollar industry in the United States alone. Professional associations and institutes, such as the Association of Contingency Planners, Business Resumption Planning Association, Contingency Planning and Recovery Institute, and their associated journals and magazines are devoted to keeping an information system (and, therefore, the business) available to both internal and external business users. The growth of e-business further emphasizes the need to maintain system availability.

Implementing a high availability solution is a complex task that requires diligent effort and a clear view of the objectives to be accomplished. The key to the process is planning and project management. This includes planning for an event, such as an outage, that may never occur, and project management with the discipline to dogmatically prepare, test, and perform for business resumption. Planning is paramount to the health of a highly available business.

This Redpaper is intended to help organize the tasks and simplify the decisions involved in planning and implementing a high availability solution. While some of the most relevent items are covered, this Redpaper cannot cover all cases because every situation is unique.

To assist IT managers with understanding the most important facts when planning to implement a high availability solution, detailed information is provided. This information can help business partners and IBMers to discuss high availability considerations with customers.

In addition, this Redpaper provides examples of highly available solutions, the hardware involved in AS/400 availability solutions, and OS/400 operating system options that add to the reliability of the system in an availability environment. Application software and how it affects an availability solution are also discussed.

Significant players in the solution are the business partners who provide the high availability middleware. In addion to discussing their products, a checklist is provided to help to establish a planning foundation.

Note: A service offering is available from IBM for examining and recommending availability improvements. Contact your IBM marketing representative for further information.

Part 1. What is high availability?

Chapter 1. Background

Chapter 2. Developing an availability plan

Chapter 3. High availability example solutions

Part 2. AS/400 high availability functions

Chapter 4. Hardware support for single system high availability

Chapter 5. Auxiliary storage pools (ASPs)

Chapter 6. Networking and high availability

Chapter 7. OS/400: Built-in availability functions

Chapter 8. Performance

Part 3. AS/400 high availability solutions

Chapter 9. High availability solutions from IBM

Chapter 10. High availability business partner solutions

Chapter 11. Application design and considerations

Chapter 12. Basic CL program model

Part 4. High availability checkpoints

Appendix A. How your system manages auxiliary storage

Appendix B. Planning for device parity protection

Appendix C. Batch Journal Caching for AS/400 boosts performance

Appendix D. Sample program to calculate journal size requirement

Appendix E. Comparing availability options

Appendix F. Cost components of a business case

Appendix G. End-to-end checklist