Instance Caging

With the steady increase in processing power, dedicating a server to a single database instance often results in inefficient resource usage.

When multiple database instances share a single server, they must share its CPU, memory, and I/O bandwidth. Oracle offers a simple and effective approach to server consolidation called “Instance Caging”.

Scenarios for Server Consolidation:

Instance Caging limits the amount of CPU an Oracle database instance consumes, using the  Oracle Database Resource Manager and the cpu_count parameter:

1)The Oracle Database Resource Manager limits the amount of CPU that the database instance consumes.

2)The cpu_count parameter specifies the limit.

Steps to enable Instance Caging:

Step 1: Setting “cpu_count”

“cpu_count” is a dynamic parameter that is not set by default. It should be set to the maximum number of CPUs that the database instance should utilize at any time.

For example, to limit the database instance to 4 CPUs:

 alter system set cpu_count = 4;


Step 2: Enabling Resource Manager

A resource plan describes how CPU resources should be allocated to processes within the database instance. For Oracle Database 11g, any of the out-of-the-box plans such as “DEFAULT_PLAN” or “DEFAULT_MAINTENANCE_PLAN” can be used.

Resource Manager can be enabled by setting the resource_manager_plan parameter:

 alter system set resource_manager_plan = 'default_plan';