Multisystem sysplex configuration with a coupling facility

This topic assumes that you have an existing multisystem sysplex and want to add a coupling facility to the configuration. In addition to the requirements for multisystem sysplex mode (see Multisystem sysplex configuration with an global resource serialization complex), you need:

A sysplex couple data set formatted with the OS/390® format utility (IXCL1DSU) (not shown).
A formatted primary CFRM couple data set shared by systems in the sysplex that use the coupling facility. The CFRM couple data set must contain at least one CFRM administrative policy.
Connectivity between the coupling facility and the systems in the sysplex requiring its use.

Purpose: Use a coupling facility to provide data sharing capability, the ability to isolate MVS™ systems through the SFM policy, or as an alternative to CTC connections for signaling.
Required System Parameters: Use the following system parameter to IPL each system in the sysplex that is to use the coupling facility:
- COUPLE=xx specifies the COUPLExx parmlib member that is updated to identify the primary CFRM couple data set.

Alternatively, you can use the SETXCF COUPLE,TYPE=CFRM,PCOUPLE command to bring the CFRM couple data set into use.

To start a policy in the CFRM data set, issue the SETXCF START,POLICY,TYPE=CFRM command, specifying the name of a CFRM policy that resides in the CFRM couple data set.

In Figure 1, SYSA and SYSB are connected to the coupling facility. (Required connections for the sysplex couple data set, Sysplex Timer, and signaling are not shown.)

Figure 1. Multisystem Sysplex Configuration with a Coupling Facility

Graphic Showing Multisystem Sysplex Configuration with a Coupling Facility