A coupling facility might support nonvolatility, that is, the ability to maintain the data stored in the coupling facility should a power outage occur. The importance of allocating a structure in a nonvolatile coupling facility is dependent on the requirements of the application. The application must document its requirement for a nonvolatile coupling facility so that the installation can properly configure its coupling facilities.

If the first connected user specifically requests with NONVOLREQ=YES that the structure be allocated in a nonvolatile coupling facility and one is available, then the request is granted. Subsequent connectors to the structure can determine whether the structure currently is in a volatile or nonvolatile coupling facility by interrogating a flag in the connect answer area (field CONAVOLATILE).