Data grids give us a great way to better utilize our computing resources. They allow us to cache objects in memory that could be located on a computer, on the LAN, or in a data center thousands of miles away. Caching data is one of the core features found in all data grid products. Understanding how to cache objects with WebSphere eXtreme Scale is the natural starting point in learning how to use its many other features to your advantage. Knowledge of where your objects live will help you create powerful grid topologies that scale linearly and keep up with the demand of your applications. WebSphere eXtreme Scale will provide your applications with fast access to remote objects, while giving you a much larger cache to rely on than you would have without a data grid. It allows us to logically join numerous computers together, whether the hardware is real or virtual, and create grids that can store terabytes of live Java objects, all while avoiding costly database hits and transformations to and from SQL statements.
You should now feel comfortable getting started with WebSphere eXtreme Scale, and creating ObjectGrid instances by using the programmatic API, or by creating a simple XML configuration file. Explore what happens when you examine the ObjectMap instances and BackingMaps with a debugger after puts and transaction commits.
You should be familiar with local ObjectGrid instances. As we explore more features of WebSphere eXtreme Scale, you will be able to tell when using a local instance is right for the situation, and when a distributed grid is more suitable. In Chapter 2, we'll find out more about interacting with data in the grid.