Single-system sysplex configuration

In single-system sysplex mode, you need a formatted primary sysplex couple data set on each system before you IPL the system.

Purpose: Use single-system sysplex mode when you want XCF services on the system but do not need XCF or XES coupling services between systems. For example, you might want to implement a WLM policy on a single system, which requires a sysplex couple data set and a WLM couple data set, or test multisystem applications.
Considerations: Multisystem applications can define XCF groups on the system and members of the group can communicate with their group members on the same system, but they cannot use signaling services to communicate with members on other systems. Note that, because a sysplex couple data set is in use, permanent status recording (LASTING=YES on the IXCJOIN macro) is available for group members on the single-system sysplex.
Consider this a temporary configuration until a multisystem sysplex is established.
Required System Parameters: Use the following parameters to IPL the system:
- COUPLE=xx specifies the COUPLExx parmlib member that describes the single-system sysplex for the system. COUPLExx must specify at least a sysplex name and a primary sysplex couple data set name. The sysplex couple data set must be unique for that system. COUPLExx must also specify the couple data set for any function, such as WLM, that you plan to use.
- PLEXCFG=MONOPLEX indicates that the system is to be initialized as a single-system sysplex. Note that the system cannot migrate to a multisystem sysplex unless you specify PLEXCFG=MULTISYSTEM.

Figure 1 shows a single-system sysplex (SYSA) connected to a sysplex couple data set and three independent systems. To migrate SYSB, SYSC, and SYSD into the sysplex, you must specify PLEXCFG=MULTISYSTEM for each system.

Figure 1. Configuration with a Single-System Sysplex and Three Independent Systems

Graphic Showing Configuration with a Single-System Sysplex and Three Independent Systems