System and method for restoring data from secondary volume to primary volume in a data storage system

1. A storage control system for restoring a remote point-in-time copy of data to a primary volume from a secondary volume, said secondary volume adapted to provide information of remote data stored on at least one remote storage disk, the system comprising:

at least one local storage disk;

a primary storage controller that conducts a request for the remote point-in-time copy; and

a secondary storage controller coupled to the primary storage controller to receive the request from the primary storage controller and to transfer the remote point-in-time copy from the secondary storage controller to the primary storage controller thereby creating a local point-in-time copy;

said primary storage controller adapted to configure the primary volume to comprise information of the local point-in-time copy located on at least one local disk.

2. A storage control system as defined in claim 1 wherein the secondary storage system receives the point-in-time copy through an asynchronous remote copy process.

3. A storage control system for restoring a remote point-in-time copy of data to a primary volume from a secondary volume, said secondary volume adapted to provide information of remote data stored on at least one remote storage disk, the system comprising:

at least one local storage disk;

a primary storage controller that conducts a request for the remote point-in-time copy; and

a secondary storage controller coupled to the primary storage controller to receive the request from the primary storage controller and to transfer the remote point-in-time copy from the secondary storage controller to the primary storage controller thereby creating a local point-in-time copy, wherein the secondary storage system receives the point-in-time copy through an asynchronous remote copy process;

said primary storage controller adapted to configure the primary volume to comprise information of the local point-in-time copy located on at least one local disk, wherein the primary storage controller further comprises a snap volume to facilitate the asynchronous remote copy process.

4. A storage control system for restoring a remote point-in-time copy of data to a primary volume from a secondary volume, said secondary volume adapted to provide information of remote data stored on at least one remote storage disk, the system comprising:

at least one local storage disk;

a primary storage controller that conducts a request for the remote point-in-time copy; and

a secondary storage controller coupled to the primary storage controller to receive the request from the primary storage controller and to transfer the remote point-in-time copy from the secondary storage controller to the primary storage controller thereby creating a local point-in-time copy;

said primary storage controller adapted to configure the primary volume to comprise information of the local point-in-time copy located on at least one local disk, wherein the primary storage controller further comprises memory allocated to store a lookup table identifying remote copy occurrences.

5. A storage control system as defined in claim 1 further comprising an application host system coupled to the primary storage controller, said application host system comprising a mainframe computer system.

6. A storage control system as defined in claim further comprising a secondary host system coupled to the secondary storage controller.

7. A storage control system as defined in claim wherein the secondary system is remotely located from the primary system.

8. A storage control system for restoring a remote point-in-time copy of data to a primary volume from a secondary volume, said secondary volume adapted to provide information of remote data stored on at least one remote storage disk, the system comprising:

at least one local storage disk;

a primary storage controller that conducts a request for the remote point-in-time copy; and

a secondary storage controller coupled to the primary storage controller to receive the request from the primary storage controller and to transfer the remote point-in-time copy from the secondary storage controller to the primary storage controller thereby creating a local point-in-time copy;

said primary storage controller adapted to configure the primary volume to comprise information of the local point-in-time copy located on at least one local disk, wherein only predetermined portions of the point-in-way copy are restored.

9. A storage control system as defined in claim 8 wherein the system further comprises:

a bit map data structure associated with the primary volume, the bit map structure identifying physical portions of at least one primary volume; and

the request for point-in-time copy comprises information related to the bit map structure.

10. A method of restoring data from a secondary storage system to a primary storage system, wherein the secondary system is remotely located from the primary system and the secondary system receives backup data transmissions via a communications link from the primary storage system, the restoring method comprising:

identifying a valid remote point-in-time copy of the data on the secondary system;

requesting the secondary system transmit data associated with the remote point-in-time copy;

transmitting the data associated with the point-in-time copy from the secondary system to the primary system; and configuring the primary system to access the transmitted data.

11. A method of restoring data as defined in claim 10 wherein the backup data transmissions conducted from the primary storage system to the secondary storage system comprise asynchronous data transmissions.

12. A method of restoring data from a secondary storage system to a primary storage system, wherein the secondary system is remotely located from the primary system and the secondary system receives backup data transmissions via a communications link from the primary storage system, the restoring method comprising:

identifying a valid remote point-in-time copy of the data on the secondary system;

requesting the secondary system transmit data associated with the remote point-in-time copy;

transmitting the data associated with the point-in-time copy from the secondary system to the primary system; and

configuring the primary system to access the transmitted data, wherein the backup data transmissions conducted from the primary storage system to the secondary storage system comprise asynchronous data transmissions;

wherein the primary storage system comprises a primary volume and a snap volume wherein the snap volume maps to the same physical locations as the primary volume said method further comprising the following step:

asynchronously transmitting backup copies of data from the primary storage system to the secondary storage system using the snap volume.

13. A method of restoring data as defined in claim 12 wherein the secondary storage system comprises a secondary volume and a secondary snap volume wherein the secondary snap volume maps to the same physical locations as the secondary volume, said method further comprising the following step:

asynchronously transmitting the point-in-time backup copy from the secondary storage system to the primary storage system using the secondary snap volume.

14. A method of restoring data as defined in claim 10 wherein the data is on a secondary disk array.

15. A method of restoring data from a secondary storage system to a primary storage system, wherein the secondary system is remotely located from the primary system and the secondary system receives backup data transmissions via a communications link from the primary storage system, the restoring method comprising:

identifying a valid remote point-in-time copy of the data on the secondary system;

requesting the secondary system transmit data associated with the remote point-in-time copy;

transmitting the data associated with the point-in-time copy from the secondary system to the primary system; and

configuring the primary system to access the transmitted data, wherein the point-in-time copy relates to predetermined portions of a volume.

16. A method of restoring data as defined in claim 10 wherein the point-in-time copy relates to a complete volume.

17. A program storage medium, readable by a computer, tangibly embodying a program of instructions executable by said computer for restoring a point-in-time copy of computer readable data to a local storage system having at least one local storage disk from a remote storage system having at least one remote storage disk, the program comprising instructions for:

identifying a valid point-in-time copy present on the remote storage disk;

requesting the point-in-time copy to be transferred to the local storage system;

transferring the point-in-time copy to the local storage system; and

storing the point-in-time copy to the local storage disk.