Writing Sample: White paper (Introduction)

Automated Recovery Management with HACMP/XD and PPRC

Overview
The success of your business depends on the availability of your applications, networks, and data. To thrive in today's competitive market, information must flow freely to wherever it is needed in the company, whenever it is needed. If your profit depends on real-time online processing systems, then you are vulnerable to a profound negative impact should a catastrophe cripple your data center. A catastrophe could be as dramatic as an earthquake or a hurricane, or as mundane as a power failure, water main break, or loss of a network or storage adapter. Whatever the cause, every minute of downtime could cost you lost revenue, lost opportunity, and even customer loyalty.

You must be able to respond quickly to restore essential services when a disaster strikes. Maintaining backup tapes at another site is not enough. You face an unknown amount of downtime before you can reestablish service, and chances are that the data you restore is already out of date. Meanwhile, your employees are idle, your customers worry, and you lose business. What you need is a solution that ensures that critical data and applications remain available, no matter what.

Protect Your Business from The Cost of Downtime
IBM addresses your need for continuous access to your system with a suite of hardware and software products designed to maintain high availability of your applications, data, servers, and storage. A disaster recovery plan that includes geographically dispersed Enterprise Storage Servers (ESS), Peer to Peer Remote Copy (PPRC) and High Availability Cluster Multi-Processing eXtended Distance for AIX (HACMP/XD) will automate the real-time replication of your applications and data while monitoring and maintaining the availability of your system. These three products work together as an integrated system to provide:

• Automatic backup and recovery after failures - The recovery of your business-critical applications and data after a wide range of system failures is not dependent on the availability of any one component.
• Automated control of data mirrors - The complicated tasks of establishing, suspending, reversing, and resynchronizing data mirrors are automatic, thus reducing the chance of data loss or corruption due to user error.
• Easier execution of planned system outages - Tools for user-controlled operations help you gracefully bring individual system components offline for scheduled maintenance while minimizing the downtime experienced by the end users.

If a catastrophe hits your data center, HACMP/XD will work in concert with ESS Copy Services PPRC to automatically recover your business-critical applications and data. In just minutes your users can resume normal business operations at your mirrored site. Each component plays the following role in your environment:

• Enterprise Storage Server (ESS) - IBM's enterprise-level storage system provides outstanding performance while keeping your data available via redundant hardware, mirrored write caches, and RAID-5 and RAID-10 protection for host volumes.
  
• Peer to Peer Remote Copy (PPRC) - IBM's hardware-based data replication solution provides real-time mirroring between two or more ESS systems, separated by distances up to 103 km utilizing ESCON links.
  
• High Availability Cluster Multi-Processing eXtended Distance for AIX (HACMP/XD) -IBM's clustering software provides automatic fallover and recovery within and between IBM pSeries servers to recover from failures of adapters, applications, individual servers or even an entire data center.

This paper provides a step-by-step example of how to use HACMP/XD and ESS Copy Services PPRC to implement a solution over a metro-wide area to keep an example application and its data highly available. The configuration consists of three pSeries Servers and two ESS systems located at separate sites.

This paper is written for Information Technology professionals who have some experience with the IBM ESS, PPRC, and HACMP. For more information on these technologies, please see the sources listed in the References section.

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