You can work in the ISPF administrative application with one service definition at a time. In order to make the service definition accessible to all systems in the sysplex, you store the service definition on a WLM couple data set. Only one service definition can be installed on the WLM couple data set at a time.
If you want to work on more than one service definition at a time, you can keep each in a distinct MVS™ partitioned data set (PDS), or in an MVS sequential data set (PS). As an MVS service definition data set, the service definition is subject to all the same functions as an MVS data set. You can restrict access to the service definition data set, send it, and copy it, as you can any MVS data set.
The service definition must be installed on a WLM couple data set, and a service policy activated. Only service policies in the service definition installed on the WLM couple data set can be activated. A WLM couple data set can have automatic backup. For more information about allocating and using a WLM couple data set, see Workload management migration.