Availability Guide for Application Design

Hewlett-Packard Company—525637-004
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Availability Guide for
Application Design
Glossary Index Figures Tables
What’s New in This Guide xi
Guide Information xi
New and Changed Information xi
About This Guide xiii
How Is This Guide Organized? xiv
Who Should Read This Introduction? xv
Where Else Can You Find Related Information? xv
Your Comments Invited xx
Notation Conventions xx
1. What Is Application Availability?
Who Ensures Application Availability? 1-1
Why Is Availability Important? 1-2
Gain a Competitive Edge 1-2
24-Hour Operations 1-2
Cost Containment 1-3
Cost Reduction 1-5
Life-Threatening Situations 1-5
Measuring Availability
1-5
Measuring Downtime in Minutes
1-6
Measuring Downtime in a Client/Server Application 1-6
Alternative Ways to Measure Downtime 1-7
What Causes Outages? 1-7
Outage Classes 1-8
Outages Are Not Limited to the Server 1-10
The NonStop Application Environment 1-10
System-Level Components 1-11
Support For Dynamic Linked Libraries 1-12
Transaction Support in the Server System 1-14
Transaction Support for the Client Process 1-14
Availability and Application Design 1-15