Programming Interface Information The DFSMSdss concurrent copy function lets you move data but minimizes the time that the data is unavailable. The user determines an appropriate time to move the data (for example, when the data is in a known state and update activity is stopped). DFSMSdss is invoked directly or via the DFSMSdss application program interface (API) to do a concurrent copy of the data. After initialization is complete, DFSMSdss releases any serialization it held on the data sets and prints a message both to SYSPRINT and the console that the CC operation is logically complete. If DFSMSdss was invoked via the API, DFSMSdss informs the caller through the UIM exit option, Eioption 24 (for more information, see CONCURRENT). The application can resume normal operation at this time. End Programming Interface Information

If for any reason data cannot be processed with concurrent copy (for example, the hardware being used does not support concurrent copy), DFSMSdss optionally uses another method of data movement and does not release the serialization until the copy is completed.

If the source device supportsdata set FlashCopy® or SnapShot, DFSMSdss can use FlashCopy or SnapShot function to provide a concurrent copy-like function called virtual concurrent copy.