Oracle Multitenant (White Paper)

Oracle White Paper
Oracle Multitenant 

Executive Overview
Oracle Multitenant is a new option for Oracle Database 12c Enterprise Edition that helps customers reduce IT costs by simplifying consolidation, provisioning, upgrades, and more. It is supported by a new architecture that allows a container database to hold many pluggable databases. And it fully complements other options, including Oracle Real Application Clusters and Oracle Active Data Guard. An existing database can be simply adopted, with no change, as a pluggable database; and no changes are needed in the other tiers of the application. The benefits of Oracle Multitenant are brought by implementing a pure deployment choice. The following list calls out the most compelling examples.

• High consolidation density. The many pluggable databases in a single container database share its memory and background processes, letting you operate many more pluggable databases on a particular platform than you can single databases that use the old architecture. This is the same benefit that schema-based consolidation brings. But there are significant barriers to adopting schema-based consolidation, and it causes ongoing operating problems. The new architecture removes these adoption barriers and operating problems.
• Rapid provisioning and cloning using SQL. A pluggable database can be unplugged from one container database and plugged into another. Alternatively, you can clone one, within the same container database, or from one container database to another. These operations, together with creating a pluggable database, are done with new SQL commands and take just seconds. When the underlying filesystem supports thin provisioning, many terabytes can be cloned almost instantaneously simply by using the keyword snapshot in the SQL command.
• New paradigms for rapid patching and upgrades. The investment of time and effort topatch one container database results in patching all of its many pluggable databases. Topatch a single pluggable database, you simply unplug/plug to a container database at adifferent Oracle Database software version.
• Manage many databases as one. By consolidating existing databases as pluggable databases, administrators can manage many databases as one. For example, tasks like backup and disaster recovery are performed at the container database level.
• Dynamic between-pluggable database resource management. Oracle Database 12c Resource Manager is extended with specific functionality to instantly control the competition between the pluggable databases within a container database. This whitepaper explains the new Oracle Database architecture, the new functionality that this brings, and the benefits that ensue. 

http://www.oracle.com/technetwork/database/multitenant-wp-12c-1949736.pdf