See z/OS MVS Setting Up a Sysplex for a complete description of the System Logger Configuration and setup requirements.
The system logger configuration you use depends on whether or not you use a coupling facility.
Coupling facility log stream configuration: Figure 1 shows all the parts involved when a system logger application writes to a coupling facility log stream. In this example, a system logger application runs on two systems in a sysplex. Both instances of the application write data to the same log stream, TRANSLOG. Each system contains a system logger address space. A system logger application uses system logger services to access the system logger capabilities.
When a system logger application writes data to a coupling facility log stream, system logger writes the data to a coupling facility list structure associated with the log stream. Then, when the coupling facility structure fills with data, system logger offloads the data to DASD log data sets.