z/VM® Guest Coupling Simulation Support is the software that simulates the hardware and software required to run an MVS™ sysplex environment as second level guests under z/VM.

z/VM is able to simulate advanced Coupling Facility (CF) and Message Facility (MF) function, namely, the ability of a set of CFs to be directly connected to one another and to z/OS® guests. z/VM Guest Coupling Simulation provides for the simulation of one or more complete parallel sysplexes within a single z/VM system image. The intent is to provide a pre-production testing platform for a coupled-system installation. The z/VM simulated environment is not intended for production use because its single points of failure negate the intent of the parallel sysplex environment. Other than the processors required, there is no special hardware needed: no coupling links and no external coupling facilities. Neither is such hardware supported. All guest operation systems coupling within a simulated sysplex can only be coupled (through simulated coupling links) to coupling facilities also running as guests of the same z/VM system. Up to 32 virtual machines can be coupled within a simulated sysplex, with each such virtual machine coupled to up to eight coupling facility virtual machines. In addition, when the processor and z/VM are so capable, each simulated coupling facility can connect to up to seven peer simulated coupling facilities. All coupled guests and simulated coupling facilities run within a single instance of the z/VM Control Program (CP).

See z/VM Running Guest Operating Systems for more information about setting up a sysplex environment, including setting up CFs under z/VM.