Oracle Application Server 10g: J2EE Deployment and Administration

Overview

10g Application Server is designed to support the most critical and highly visible systems that businesses can demand. Some systems need to be available 24 — 7 and to do that, you must eliminate any single point of failure and introduce fault tolerance. While there are many facets to high-availability systems, the focus here is the web application server.

With 10g AS you can cluster your mid tiers on separate nodes so if any one fails, work is automatically sent to the other surviving nodes. Clustering also provides an important performance boost by being able to distribute the workload over multiple nodes when there would be too much work for even the largest machine to process. Running clusters is more difficult and expensive than a simple standalone, but 10g AS is designed to make this configuration easier to manage, as you'll see in this chapter.

In this chapter, we'll cover the following:

• Clustering overview. Identify what clustering is, how it works, and why it's used from a non-Oracle-specific perspective. This provides a basis for understanding 10g AS clustering.

• 10g AS clustering. Discuss in detail Oracle's 10g AS clustering implementation, its architecture, benefits, and how it works.

• Creating a farm. A prerequisite to building clusters is establishing farms and we cover why and how that's done. This includes coverage of a 10g AS Infrastructure installation and how to join those mid tiers into that software.

• Creating clusters. We show you how to actually build a cluster with two J2EE mid- tier instances fronted by Oracle Web Cache (WC). Configuration of WC for clustered environments is explained.

• Deploying clustered applications. Deploying and managing clustered applications is covered.

• Implementing failover. Clustering is often implemented for fault tolerance and we'll show you how to actually do this. The steps and examples prove this works and shows how it's done.