A database cloud is a set of databases integrated by the Global Data Services framework into a single virtual server that offers one or more global services, while ensuring high performance, availability and optimal utilization of resources. Global Data Services manages these virtualized resources with minimum administration overhead, and allows the database cloud to quickly scale to handle additional client requests. The databases that constitute a cloud can be globally distributed, and clients can connect to the database cloud by simply specifying a service name, without needing to know anything about the components and topology of the cloud.
A database cloud can be comprised of multiple database pools. A database pool is a set of databases within a database cloud that provide a unique set of global services and belong to a certain administrative domain. Partitioning of cloud databases into multiple pools simplifies service management and provides higher security by allowing each pool to be administered by a different administrator. A database cloud can span multiple geographic regions. A region is a logical boundary that contains database clients and servers that are considered to be close to each other. Usually a region corresponds to a data center, but multiple data centers can be in the same region if the network latencies between them satisfy the service-level agreements of the applications accessing these data centers.
Global services enable you to integrate locally and globally distributed, loosely coupled, heterogeneous databases into a scalable and highly available private database cloud. This database cloud can be shared by clients around the globe. Using a private database cloud provides optimal utilization of available resources and simplifies the provisioning of database services.
Oracle Database Global Data Services Concepts and Administration Guide for more information about global services