System and method for storage virtualization

• US 6,845,403 B2
• Filed: 10/31/2001
• Issued: 01/18/2005
• Est. Priority Date: 10/31/2001
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Chadalapaka, Mallikarjun B
• Primary Examiner(s): Gaffin, Jeffrey
• Assistant Examiner(s): Nguyen, Mike
• Application Number:
  US09/999,026
• Publication Number:
  US 20030084209A1
• Time in Patent Office: 1,175 Days
• Field of Search: 710 5- 7, 710/74, 710/105, 710111-114, 710305-317, 711111-114
• US Class Current: 710/5
• CPC Class Codes: G06F 2003/0697 device management, e.g. handlers, drivers, I/O schedulers
• CPC Class Codes: G06F 3/0601 Interfaces specially adapted for storage systems
• CPC Class Codes: G06F 3/0617 in relation to availability
• CPC Class Codes: G06F 3/0659 Command handling arrangements, e.g. command buffers, queues, command scheduling
• CPC Class Codes: G06F 3/0664 at device level, e.g. emulation of a storage device or system
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]

Abstract

The present invention is generally directed to a system and method for virtualizing storage in a networked system. In accordance with one aspect of the invention, in a system having an initiator and at least one storage device, an inventive method determines, based upon a SCSI command received by a manager from the initiator, which of the data storage devices are implicated by the SCSI command. The method then forms an iSCSI command that is sent from the manager to each of the implicated storage devices, and receives at the manager an iSCSI response from each of implicated storage devices, after each of the storage devices has completed its implicated data transactions with the initiator. Finally, the method forms a SCSI response that is sent by the manager to the initiator. A corresponding system is also provided.

Claims

1. In a system having an initiator and at least one storage device, a manager for virtualizing storage among the at least one storage device comprising:

logic configured to determine, based upon a SCSI command received from the initiator, which of the data storage devices are implicated by the SCSI command;

logic configured to form an iSCSI command that is sent to each of the implicated storage devices;

logic configured to receive an iSCSI response from each of the implicated storage devices, after each of the storage devices has completed its implicated data transactions with the initiator; and

logic configured to form a SCSI response that is sent to the initiator.

2. The system as defined in claim 1, wherein the logic configured to form a SCSI response forms the response that is inferred by aggregation of independent responses from the storage devices.

3. The system as defined in claim 1, wherein the manager includes program code configured to execute a software process.

4. The system as defined in claim 1, further including logic configured to evaluate the SCSI command received from the initiator, wherein the logic configured to evaluate is further configured to examine an IP (Internet Protocol) address of the initiator.

5. The system as defined in claim 1, further including logic configured to determine, based upon the SCSI command received from the initiator, whether to form an iSCSI command to be sent to storage devices or form an immediate response to be sent to the initiator.

6. The system as defined in claim 1, wherein the iSCSI command sent to each of the implicated storage devices includes an offset value, which specifies an offset that the storage device receiving the iSCSI command modifies a Buffer Offset value that is contained in a protocol defining communications between the storage device and the initiator.

7. The system as defined in claim 6, wherein the offset value is added to the Buffer Offset value in communications with the initiator for R2T (request to transfer) and SCSI Read PDUs (protocol data units).

8. The system as defined in claim 6, wherein the offset value is subtracted from the Buffer Offset value in SCSI Write Data PDUs that the storage device receives from the initiator.

9. The system as defined in claim 1, wherein the iSCSI command sent to each of the implicated storage devices includes an Initiator Task Tag that was communicated from the initiator to the manager in the SCSI command.

10. The system as defined in claim 1, wherein the iSCSI command sent to each of the implicated storage devices includes a session identifier of the session on which the manager received the SCSI command.

11. The system as defined in claim 1, wherein the iSCSI command sent to each of the implicated storage devices includes an IP (Internet Protocol) address of the initiator.

12. In a system having an initiator and at least one storage device, a method for virtualizing storage among the at least one storage device comprising:

determining, based upon a SCSI command received by a manager from the initiator, which of the data storage devices are implicated by the SCSI command;

forming an iSCSI command that is sent from the manager to each of the implicated storage devices;

receiving at the manager a SCSI response from each of implicated storage devices, after each of the storage devices has completed its implicated data transactions with the initiator; and

forming a SCSI response that is sent by the manager to the initiator.

13. The method as defined in claim 12, further including the step of evaluating an IP (Internet Protocol) address of the initiator.

14. The method as defined in claim 12, further including the step of determining, based upon the SCSI command received from the initiator, whether to form an iSCSI command to be sent to storage devices or form a direct response to be sent to the initiator.

15. The method as defined in claim 12, wherein the step of forming the iSCSI command sent to each of the implicated storage devices includes providing an offset value, which specifies an offset that the storage device receiving the iSCSI command modifies a Buffer Offset value that is contained in a protocol defining communications between the storage device and the initiator.

16. The method as defined in claim 15, wherein the offset value is added to the Buffer Offset value in communications with the initiator for R2T (request to transfer) and SCSI Read PDUs (protocol data units).

17. The method as defined in claim 15, wherein the offset value is subtracted from the Buffer Offset value in SCSI Write Data PDUs that the storage device receives from the initiator.

18. The method as defined in claim 12, wherein the step of forming an:

iSCSI command sent to each of the implicated storage devices includes providing an Initiator Task Tag that was communicated from the initiator to the manager in the SCSI command.

19. The method as defined in claim 12, wherein the step of forming an iSCSI command sent to each of the implicated storage devices includes providing a session identifier of the session on which the manager received the SCSI command.

20. The method as defined in claim 12, wherein the step of forming an iSCSI command sent to each of the implicated storage devices includes providing an IP (Internet Protocol) address of the initiator.

21. In a system having an initiator and at least one storage device, a manager for virtualizing storage among the at least one storage device comprising:

means for determining, based upon a SCSI command received from the initiator, which of the data storage devices are implicated by the SCSI command;

means for forming an iSCSI command that is sent to each of the implicated storage devices;

means for receiving a SCSI response from each of the implicated storage devices, after each of the storage devices has completed its implicated data transactions with the initiator; and

means for forming a SCSI response that is sent to the initiator.

22. In a system having an initiator and at least one storage device, a method for virtualizing storage among the at least one storage device comprising:

determining, based upon a command having a defined protocol received by a manager from the initiator, which of the data storage devices are implicated by the command, wherein the defined protocol is one defining a family of interfaces for requesting service from input/output devices;

forming a unique protocol command that is sent from the manager to each of the implicated storage devices;

receiving at the manager a response having the unique protocol from each of the implicated storage devices, after each of the storage devices has completed its implicated data transactions with the initiator; and

forming a response having the defined protocol that is sent by the manager to the initiator.

23. The method as defined in claim 22, wherein the step of forming a unique protocol command that is sent from the manager to each of the storage devices forms a protocol command that encapsulates a SCSI protocol.