Oracle Tips by Burleson

Oracle10g Grid Computing with RAC
Chapter 6 - Install, Configure and Database Creation

Cluster File System (CFS)

However, with implementation of the ODM interface, Oracle RAC accesses data files stored on CFS, bypassing the file system buffer and file system locking processes. Oracle manages its own consistency mechanism. The ODM facility is automatically invoked with RAC.

VCS Framework and Service Groups

Veritas Cluster Server (VCS) is the overall framework that controls the Oracle RAC database and other required essential resources such as shared storage and listener. VCS acts as a director of operations. All activities within Oracle RAC and its infrastructure are managed with the VCS framework.

VCS manages its resources in the form of a group. A collection of resources of different types for a given application or task is called a service group. Service groups act as containers for all the necessary components and resources of an application. They are defined and managed as a single unit. A service group definition typically consists of:

• The keyword ‘group’ (in the configuration file).
   

• Name of the service group.
   

• The service group’s attribute values (enclosed in parentheses). VCS predefine service group attributes.
   

• The definition of service group resources. (with attributes/values).
   

• The dependencies between the service group resources.