The "g" in Oracle Database 10g signifies Oracle's focus on enabling grid computing with this database release. Grids are simply pools of computers that provide needed resources for applications on an as-needed basis. The goal is to provide computing resources that transparently scale to the user community, much as an electrical utility company can deliver power to meet peak demand by accessing energy from other power providers' plants via a power grid. Computing grids enable this dynamic provisioning of CPU and data resources (shown in Figure 11-6). Oracle Database 10g with RAC form the foundation for the provisioning of these resources.
Oracle Database 10g adds several important features that enable the delivery of resources when needed via a grid:
Dynamic Service Provisioning
This feature automatically allocates and reallocates server resources based on configuration and failover rules. Service requests are automatically routed to the server with the least load. If a server fails, the surviving services are automatically reallocated to the available servers.
Web services
Web services are also an inherent part of the grid landscape, because applications running on the grid want to use the same type of transparent access to components (or services) that users have to applications. New database web services provide support for queries, messaging, and DML, can access Java and PL/SQL, and can provide full XML support.
Rolling upgrades
Oracle Database 10g facilitates the management of large numbers of nodes through rolling upgrades. A rolling upgrade allows you to bring down some of the nodes in the grid, upgrade their software, and then bring them back online as part of the grid. You can then repeat this procedure with the other nodes. The end result is that you can achieve a complete upgrade of your Oracle database software without having to bring down the database.
Automatic Storage Management
The ASM system also enables management of large numbers of nodes by implementing automatic data rebalancing across disks, as well as easy addition of new disks to the overall pool of storage.
Enterprise Manager
Enterprise Manager 10g is designed to manage a grid infrastructure from a central location, including RAC databases, storage, Oracle Application Servers, and network services.