5.2 Cluster terminology

There is a very good chance that some of the terminology that we use in this book will be new or at least a little different from what you are accustomed to. At this point, then, it will be helpful to define some of the terminology related to clustering. One problem is that some vendors typically use definitions for clustering that best promote their products, while other vendors may use a different definition or name for the same thing. We can only imagine the potential for conflicting terminology at the new and bigger Compaq. Now that Compaq has absorbed the former Digital Equipment and Tandem Computer Corporations, you will likely get different definitions depending on which building you visit at Compaq. People who come from a Tandem or Digital background and who have been managing clusters for the past 10 to 20 years will have in their minds definitions that are based on their respective clustering technology and products. Today, the architectures used to build e-commerce solutions have different requirements; hence, their designs and implementations will naturally be geared to meeting the needs of Internet ISPs. The WEB-centric applications have their own unique requirements for implementing high-availability solutions. The way this is done today is slightly different from the way it was done in the past. It is essential for those of us who have been in the business for some time now to approach today's e-commerce solutions that are built on Windows NT for what they