Chapter 2: WebSphere Scalability and Availability


Overview

I touched on performance during Chapter 1 but have yet to dive into WebSphere scalability and availability paradigms . Therefore, this chapter explores what it means to have a highly scalable and highly available WebSphere-based implementation.

The terms scalability and availability are synonymous with high-performance computing. Since the dawn of the computing age, systems have been designed with these two principles in mind, usually alongside their partnering paradigm, performance.

To restate , the three key measures of high-performance computing are the following:

  • Availability

  • Performance

  • Scalability

How well a system rates against any of these three aspects of computing determines the platform's overall compliance to high-end computing platform designs. In other words, there's no sense having a massively scalable system when it's riddled with single points of failure, indicating low availability. That said, as you explore this and subsequent chapters, your application environment may not constitute or demand massive amounts of scalability and availability. For instance, 99.999-percent availability isn't always the Holy Grail; sometimes 99-percent availability is satisfactory.

Size doesn't necessarily come into play here either. Scalability, for example, may mean you can double your log file data easily, but the system may only consist of two application servers, each with a single Central Processing Unit (CPU).

This chapter helps you gauge what these terms really mean and applies them to some example WebSphere implementations . The bottom line is that every WebSphere system will be different. Moreover, every WebSphere system will be subject to different business factors. Again, it may be satisfactory that a WebSphere implementation needs only 95-percent availability! In a case such as this, meeting 95-percent availability may even be deemed as highly available; to another company, this may be a downright time bomb!

You'll now explore these concepts in detail before looking at some case studies.




Maximizing Performance and Scalability with IBM WebSphere
Maximizing Performance and Scalability with IBM WebSphere
ISBN: 1590591305
EAN: 2147483647
Year: 2003
Pages: 111
Authors: Adam G. Neat

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