CHAPTER 1
Introduction to High Availability and Scalability

In today’s fast-paced world, data and application availability can make or break a business. With access to these businesses granted via the ubiquitous and “always-on” Internet, data availability is an extremely important component in any business function.

Database systems are growing at an enormous rate in terms of the number of simultaneously connected and active users as well as the volume of data they handle. Even though the servers used to store huge, active databases have also improved in performance and capacity, a single server, powerful though it may be, is frequently unable to handle the database load and capacity requirements for these active databases. This factor makes it necessary to scale the processing capacity or scale the hardware or software to accommodate these requirements.