Managing coupling facility resources

Sysplex support for a coupling facility satisfies customers' requirements for:

Data sharing across the systems in a sysplex
Resource sharing across the systems in a sysplex
Maintaining the integrity and consistency of shared data
Maintaining the availability of a sysplex.

The coupling facility makes data sharing possible by allowing data to be accessed throughout a sysplex with assurance that the data will not be corrupted and that the data will be consistent among all sharing users. The coupling facility provides the medium in which users of coupling facility structures can reconstruct shared data should a failure occur and can be used to assist in the isolation of failing systems.

The coupling facility is a shareable storage medium, but not what we usually consider a shared storage device. Rather, a coupling facility is licensed internal code (LIC) running in a special type of PR/SM™ logical partition (LPAR) in certain z/Series and S/390® processors. A coupling facility can be shared by the systems in one sysplex only; it cannot be shared simultaneously by multiple sysplexes.

The following topics describe what a coupling facility is and how to include one or more coupling facilities in your sysplex:

Planning for a coupling facility outlines the steps your installation must perform to use a coupling facility.
Planning a coupling facility policy describes how to set up the policy that will govern your use of a coupling facility.
An installation guide to duplexing rebuild describes the installation tasks required to enable system-managed duplexing rebuild.
The role of CFRM in a sysplex explains the services that coupling facility resource management provides to manage a coupling facility in your installation.
Resource allocation in the coupling facility describes how the storage in a coupling facility is allocated, based on your requirements and those of the application using a coupling facility.
Operating in a coupling facility environment describes the operator intervention that might be required with a coupling facility in a sysplex and summarizes the operator commands with which you interface with a coupling facility.
Coupling facility structures for IBM products provides a chart of coupling facility structures that are used by IBM® products and where to find additional information about the structures.