Concurrent copy provides point-in-time data consistency, which is not possible with other online data dump techniques. The system serializes access to the data that you are dumping or copying just long enough for the concurrent copy session to initialize. This serialization takes a matter of seconds. Compare this to the quiesce and backup technique, which makes data unavailable for the entire duration of the dump (possibly hours).
The copy is logically complete as soon as you have initialized the concurrent copy environment. At that point, concurrent copy protects the original state of the data. After logical completion, the data is once again available for unrestricted application access. The copy is physically complete once the concurrent copy process finishes copying the data to the output device.
You can use concurrent copy to back up any data that can be backed up using DFSMSdss (or DFDSS) because DFSMSdss is the external interface to concurrent copy.
For example, you can back up IMS™ databases by using DFSMSdss. During the recovery process, IMS database recovery control (DBRC) coordinates recovery of the DFSMSdss dump and the application of updates from the IMS log. Conversely, DB2® (before Version 3) does not support those activities. Consequently, do not use concurrent copy with DB2 releases earlier than Version 3.