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High Availability on the AS/400 System: A System Manager’s Guide

An IBM Redpaper publication

Note: This is publication is now archived. For reference only.


Published on 31 May 2001

  1. .PDF (1.8 MB)

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IBM Form #: REDP-0111-00

Authors: Susan Powers, Nick Harris, Ellen Dreyer Andersen, Sue Baker and David Mee

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    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.

    Table of Contents

    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


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