Availability Guide for Application Design

Contents

Availability Guide for Application Design—525637-004

2. Overview of Server and Network Fault Tolerance

1. What Is Application Availability? (continued)

Design Program Modules for Availability 1-15

Provide Instrumentation 1-19

Provide Application Performance Data 1-20

Think About Protection From Coding Errors 1-20

Think Ahead About Changing the Application Online 1-21

Analyzing Outages and Developing a Strategy 1-22

Establishing Your Goals 1-22

Collecting Outage Data 1-23

Establishing a Phased Approach 1-24

HP Services Help You Manage Availability 1-25

Availability and HP Products 1-26

2. Overview of Server and Network Fault Tolerance

What Is Fault Tolerance? 2-1

Fault Tolerance in the Server System 2-2

Parallel Hardware Components 2-4

Fault Isolation 2-8

Extensive Hardware Error Checking 2-10

System Process Pairs 2-12

Instrumentation of System Components 2-16

Fault Tolerance in a Client/Server Network 2-17

Additional Availability Problems in Client/Server Networks 2-17

Benefits of a Continuously Available Server 2-19

Use a Fault-Tolerant LAN 2-21

Use Fault-Tolerant Clients 2-22

Use Fault-Tolerant Network Services 2-22

The HP Integrity NonStop NS-Series Server Provides Another Level of

Availability 2-23

ServerNet Clustering for Availability and Performance 2-26

3. Improving Availability on the Internet

Open Standards 3-1

Standards and the Operating System 3-2

Standards and Languages 3-3

Standards and the Database 3-4

Standards and the Network 3-6

Standards and Application Integration 3-7