Non-disruptive configuration of a virtualization controller in a data storage system

1. A method for configuring a data storage system, comprising:

establishing a first data path between a host and a storage controller that interfaces with the host and a plurality of storage devices for storing data, wherein the host accesses the storage devices through the storage controller, wherein the host and the storage devices are in a communication zone;

adding a virtualization controller to map the storage devices to a plurality of virtual volumes;

establishing a second data path between the host and the storage devices through the virtual volumes, wherein the host recognizes the virtual volumes as an alternate data path to the first data path between the hosts and the storage devices;

removing the first data path between the host and the storage controller in response to establishing the second data path, wherein the virtualization controller is configured without disrupting I/O operations between the host and the storage devices; and

performing I/O operations between the host and the storage devices through the second data path and the virtualization controller.

2. The method of claim 1 , wherein the storage devices are coupled to the storage controller, and the storage controller is coupled to the host.

3. The method of claim 1 , further comprising disabling data caching in the virtualization controller during the configuration.

4. The method of claim 1 , wherein the I/O operations between the host and the storage devices through the second data path are managed by a multi-path driver in the host.

5. The method of claim 1 , wherein the virtual volumes are mapped one-to-one to the storage devices.

6. The method of claim 1 , wherein the virtual volumes are image mode virtual disks provided by the virtualization controller.

7. A computer program product comprising a non-transitory computer readable storage medium having computer readable program code embodied therewith, the computer readable program code that when executed by a processor performs operations, the operations comprising:

establishing a first data path between a host and a storage controller that interfaces with the host and a plurality of storage devices for storing data, wherein the host accesses the storage devices through the storage controller, wherein the host and the storage devices are in a communication zone;

adding a virtualization controller to map the storage devices to a plurality of virtual volumes;

establishing a second data path between the host and the storage devices through the virtual volumes, wherein the host recognizes the virtual volumes as an alternate data path to the first data path between the hosts and the storage devices;

removing the first data path between the host and the storage controller in response to establishing the second data path, wherein the virtualization controller is configured without disrupting I/O operations between the host and the storage devices; and

performing I/O operations between the host and the storage devices through the second data path and the virtualization controller.

8. The computer program product of claim 7 , wherein the storage devices are coupled to the storage controller, and the storage controller is coupled to the host.

9. The computer program product of claim 7 , wherein the operations further comprise disabling data caching in the virtualization controller.

10. The computer program product of claim 7 , wherein the operations further comprise managing the I/O operations between the host and the storage devices through the second data path.

11. The computer program product of claim 7 , wherein the operations further comprise recognizing alternate data paths between the host and the storage devices through the virtualization controller.

12. The computer program product of claim 7 , wherein the virtual volumes correspond to SCSI unique identifiers of the storage devices.

13. The computer program product of claim 7 , wherein the operations further comprise mapping the virtual volumes to the storage devices.

14. The computer program product of claim 7 , wherein the virtual volumes are image mode virtual storage devices provided by the virtualization controller.

15. A controller system configured to be coupled to a storage area network (SAN), the controller system comprising:

a memory;

a processor coupled to the memory and configured to:

establish a first data path between a host and a storage controller that interfaces with the host and a plurality of storage devices for storing data, wherein the host accesses the storage devices through the storage controller, wherein the host and the storage devices are in a communication zone;

add after establishing the first data path, a virtualization controller to map the storage devices to a plurality of virtual volumes and establishes a second data path between the host and the storage devices through the virtual volumes, wherein the host recognizes the virtual volumes as an alternate data path to the first data path between the hosts and the storage devices;

removing the first data path between the host and the storage controller in response to establishing the second data path, wherein the virtualization controller is configured without disrupting I/O operations between the host and the storage devices; and

performing I/O operations between the host and the storage devices through the second data path and the virtualization controller.

16. The controller system of claim 15 , wherein data caching in the controller system is disabled during a configuration of the controller system.

17. The controller system of claim 15 , wherein the I/O operations between the host and the storage devices through the second data path are managed by a multi-path driver in the host.

18. The controller system of claim 15 , further comprising a host driver for recognizing alternate data paths between the host and the storage devices through the system.

19. The controller system of claim 15 , wherein the virtual volumes correspond to SCSI unique identifiers of the storage devices.

20. The controller system of claim 15 , wherein the virtual volumes are mapped one-to-one to the storage devices.