TECHNIQUES FOR DYNAMICALLY TRACKING LOGICAL UNITS MOVING BETWEEN INPUT/OUTPUT PORTS OF A STORAGE AREA NETWORK TARGET

• US 20140157046A1
• Filed: 11/30/2012
• Published: 06/05/2014
• Est. Priority Date: 11/30/2012
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: ANUMALASETTY, KIRAN KUMAR, AYYAGARI, PHANI KUMAR, MADDALI, SUDHIR, MARUPAKA, RAMESH KUMAR, RATHI, SANKET
• Granted Patent: US 9,304,875 B2
• Time in Patent Office: Days
• US Class Current: 714/6.22
• CPC Class Codes: G06F 11/2005 using redundant communication controllers
• CPC Class Codes: G06F 11/2007 using redundant communication media

Abstract

A technique for operating a storage area network includes detecting an input/output operation failure associated with a logical unit number, which is associated with a first target port. The technique also includes determining, subsequent to the detected input/output operation failure, whether the logical unit number is associated with a second target port. Finally, the technique includes routing subsequent input/output operations for the logical unit number to the logical unit number via the second target port, in response to determining that the logical unit number is associated with the second target port.

Claims

1. A method of operating a storage area network, comprising:

detecting, by a data processing system, an input/output operation failure associated with a logical unit number, wherein the logical unit number is associated with a first target port;

determining, by the data processing system, whether the logical unit number is associated with a second target port subsequent to the detected input/output operation failure; and

routing, by the data processing system, subsequent input/output operations for the logical unit number to the logical unit number via the second target port in response to determining that the logical unit number is associated with the second target port.

2. The method of claim 1, wherein the determining, by the data processing system, whether the logical unit number is associated with a second target port further comprises:

determining, by the data processing system, a first identifier of a target associated with the first target port;

issuing, by the data processing system, a report logic unit number query to one or more target ports with the first identifier;

receiving, by the data processing system, one or more logical unit number identifiers in response to the report logic unit number query;

issuing, by the data processing system, a device identifier inquiry for the one or more logical unit number identifiers reported;

receiving, by the data processing system, one or more device identifiers in response to the device identifier inquiry; and

comparing a device identifier of the logical unit number to the one or more device identifiers received, wherein when the device identifier matches one of the one or more device identifiers received the logical unit number is associated with the second target port.

3. The method of claim 2, wherein the first identifier is a world wide node number.

4. The method of claim 2, wherein the device identifiers are device serial numbers.

5. The method of claim 1, wherein the first and second target ports are associated with a same storage area network target.

6. The method of claim 1, wherein the first and second target ports are respective ports of a redundant array of inexpensive disks array.

7. The method of claim 1, wherein the first and second target ports are respective ports of a hard disk drive array of a storage area network.

8. A computer program product, comprising:

a computer-readable storage medium; and

computer-readable code for tracking logical unit numbers between input/output ports of storage area network targets embodied on the computer-readable storage medium, wherein the computer-readable code, when executed by a processor of a data processing system, causes the processor to;

detect an input/output operation failure associated with a logical unit number, wherein the logical unit number is associated with a first target port;

determine whether the logical unit number is associated with a second target port subsequent to the detected input/output operation failure; and

route subsequent input/output operations for the logical unit number to the logical unit number via the second target port in response to determining that the logical unit number is associated with the second target port.

9. The computer program product of claim 8, wherein the computer-readable code, when executed by the processor of the data processing system, further causes the processor to:

determine a first identifier of a target associated with the first target port;

issue a report logic unit number query to one or more target ports with the first identifier;

receive one or more logical unit number identifiers in response to the report logic unit number query;

issue a device identifier inquiry for the one or more logical unit number identifiers reported;

receive one or more device identifiers in response to the device identifier inquiry; and

compare a device identifier of the logical unit number to the one or more device identifiers received, wherein when the device identifier matches one of the one or more device identifiers received the logical unit number is associated with the second target port.

10. The computer program product of claim 9, wherein the first identifier is a world wide node number.

11. The computer program product of claim 9, wherein the device identifiers are device serial numbers.

12. The computer program product of claim 8, wherein the first and second target ports are associated with a same storage area network target.

13. The computer program product of claim 8, wherein the first and second target ports are respective ports of a redundant array of inexpensive disks array.

14. The computer program product of claim 8, wherein the first and second target ports are respective ports of a hard disk drive array of a storage area network.

15. A data processing system, comprising:

a memory system; and

a processor coupled to the memory system, wherein the processor is configured to;

detect an input/output operation failure associated with a logical unit number, wherein the logical unit number is associated with a first target port;

determine whether the logical unit number is associated with a second target port subsequent to the detected input/output operation failure; and

route subsequent input/output operations for the logical unit number to the logical unit number via the second target port in response to determining that the logical unit number is associated with the second target port.

16. The data processing system of claim 15, wherein the processor is further configured to:

determine a first identifier of a target associated with the first target port;

issue a report logic unit number query to one or more target ports with the first identifier;

receive one or more logical unit number identifiers in response to the report logic unit number query;

issue a device identifier inquiry for the one or more logical unit number identifiers reported;

receive one or more device identifiers in response to the device identifier inquiry; and

compare a device identifier of the logical unit number to the one or more device identifiers received, wherein when the device identifier matches one of the one or more device identifiers received the logical unit number is associated with the second target port.

17. The data processing system of claim 16, wherein the first identifier is a world wide node number.

18. The data processing system of claim 16, wherein the device identifiers are device serial numbers.

19. The data processing system of claim 15, wherein the first and second target ports are associated with a same storage area network target.

20. The data processing system of claim 15, wherein the first and second target ports are respective ports of a hard disk drive array of a storage area network.