Patent ID: 8458420

Claim:
A method, comprising: storing only those tracks that are affected by a copy services action in a file stored in a non volatile storage coupled to a storage controller during a copy services setup time; performing host input/output (I/O) operations via the file while data structures are being generated in the storage controller to copy data from source logical volumes to target logical volumes, wherein the source logical volumes and the target logical volumes are logical representations of physical storage maintained in a plurality of direct access storage devices; transferring contents of the file from the non-volatile storage to one or more of the plurality of direct access storage devices, after the data structures have been generated, wherein the host I/O operations are performed via the file while the contents of the file are being transferred to the one or more of the plurality of direct access storage devices; and resuming host I/O operations to the plurality of direct access storage devices, in response to transferring entire contents of the file to the one or more of the plurality of direct access storage devices, wherein copying of the data from the source logical volumes to the target logical volumes is performed by a copy services operation, the method further comprising: in response to determining that a copy services setup is active, performing: in response to a read request from the host for selected data, returning the selected data from the file if the file includes the selected data; and in response to determining that the copy services setup is not active, performing: determining whether the file is empty, and in response to determining that the file is not empty, in response to the read request from the host for the selected data, returning the selected data from the file if the file includes the selected data.