The FASTREPLICATION(REQUIRED | PREFERRED | NONE) keyword tells DFSMSdss how you want SnapShot to be used. The default is FASTREPLICATION(PREFERRED).

FASTREPLICATION(REQUIRED) specifies that DFSMSdss use fast replication such as SnapShot to move data. If SnapShot cannot be used, DFSMSdss issues error message ADR938E and the copy operation fails. DFSMSdss does not try any other methods of data movement.

Restriction: You cannot use the FASTREPLICATION(REQUIRED) and CONCURRENT keywords together.

FASTREPLICATION(PREFERRED) specifies that DFSMSdss attempt to use SnapShot before any other method to move data (even when you specify the CONCURRENT keyword). If SnapShot cannot be used and you have specified the CONCURRENT keyword, DFSMSdss attempts to use virtual concurrent copy. If you have not specified the CONCURRENT keyword or if virtual concurrent copy has failed, DFSMSdss uses traditional data movement methods to copy the data.

FASTREPLICATION(NONE) specifies that DFSMSdss not attempt to use SnapShot to copy data. Instead, DFSMSdss attempts to use virtual concurrent copy if the CONCURRENT keyword is specified. If virtual concurrent copy cannot be used, DFSMSdss uses traditional data movement methods to move the volume.

For more information about the FASTREPLICATION keyword, see FASTREPLICATION.