Storage in a coupling facility is divided up into distinct objects called structures. Structures are used by authorized programs to implement data sharing and high-speed serialization. Structure types are cache, list, and lock, each providing a specific function to the application. Some storage in the coupling facility can also be allocated as a dedicated dump space for capturing structure information for diagnostic purposes.

You manage a coupling facility through a policy, the coupling facility resource management (CFRM) policy. CFRM allows you to specify how a coupling facility and its resources are to be used in your installation. In a CFRM policy, you supply information about each coupling facility and each coupling facility structure that you plan to use.

Your installation can define several CFRM policies, to be used at different times depending on the workload running on the sysplex. Each of these administrative policies has its own name by which you identify it when you want to make it the active policy. Only one policy can be active in a sysplex at a time.

You create the administrative CFRM policies with an IBM® utility program, IXCMIAPU, provided in SYS1.MIGLIB. Once created, the policies reside in a CFRM couple data set. MVS™ and the authorized application use the definitions in the CFRM policy when managing the coupling facility storage.