Disclosed is a method and apparatus for optimizing memory space and improving the write performance in a data processing system having a data volume with multiple virtual copies thereof. In one embodiment of the method, a first virtual copy of a primary data volume is created. Thereafter, first data of the primary data volume is modified. A second virtual copy of the primary data volume is created after modification of the first data thereof. A write-data transaction for modifying second data of the modified primary data volume is generated after creation of the second virtual copy. The second data of the modified primary data volume is copied to memory allocated to store data of the second virtual copy. The second data of the modified primary data volume is modified after the second data is copied to the memory allocated to store data of the second virtual copy.