Planning a coupling facility policy

To set up your CFRM policy, you must know which subsystems and applications in your installation are making use of the coupling facility and what their structure requirements are. Each application specifies the structure types required and provides information as to the name and size of the structure or structures it uses. Based on this input, you must determine what is an appropriate number of coupling facilities and how best to distribute the structures within the coupling facilities.

A single coupling facility can only be used by one sysplex at a time.

To define a CFRM policy, you must:

Identify each coupling facility.
Define the amount of space within the coupling facility that you want for dumping.
Identify each structure. For each structure:
- Specify the size of each structure, the maximum size and optionally, an initial size and a minimum size.
- Specify parameters that are related to the use of storage-class memory.
- Specify a percentage value that represents a percent full threshold for the structure.
- Specify whether you want the system to automatically alter the size of a structure when it reaches a user-defined or system-defined percent full threshold.
- Specify which structures you want to duplex.
- Specify an ordered “preference list” of coupling facilities in which the structure may be allocated.
- Specify a list of structures, an “exclusion list”, that are not to be allocated in the same coupling facility as the structure.
- Specify a percent value to indicate the amount of lost connectivity to a structure that the sysplex can tolerate before MVS™ initiates a structure rebuild, if applicable.

The administrative data utility, IXCMIAPU, and an example of its use, is described in Administrative data utility.