Method to Allow a Host to Replace Logical Path Resources it Owns

• US 20090193142A1
• Filed: 01/30/2008
• Published: 07/30/2009
• Est. Priority Date: 01/30/2008
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Hathorn, Roger G., Le, Dinh H., Coronado, Juan A., Holley, Bret W.
• Granted Patent: US 8,909,827 B2
• Time in Patent Office: Days
• US Class Current: 709/238
• CPC Class Codes: G06F 3/0605 by facilitating the interaction with a user or administrator
• CPC Class Codes: G06F 3/0617 in relation to availability
• CPC Class Codes: G06F 3/0635 by changing the path, e.g. traffic rerouting, path reconfiguration
• CPC Class Codes: G06F 3/067 Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]

Abstract

A method for replacing logical path resources, a host is able to replace a logical path it owns with a new logical path. Such a system is especially applicable when the condition of “out of resources” has been reached for a port. With this system, a host is guaranteed that it can replace a logical path it owns with a new logical path. It is not necessary for a control unit to have reached its maximum number of logical paths per port. A host is able to replace one logical path with a new logical path any time.

Claims

1. A method comprising:

sending, by a host to a storage controller, a logical path replaceable notification to a logical path resource, the logical path replaceable notification indicating the logical path resource may be replaced by an owner host;

determining whether to perform a logical path replacement operation; and

performing a logical path replacement operation on the logical path having the logical path replaceable notification, the logical path replacement operation dynamically replacing the logical path resource with another logical path resource.

2. The method of claim 1 wherein:

the performing a logical path replacement operation occurs in response to an establish logical path operation.

3. The method of claim 1 wherein:

the performing a logical path replacement operation occurs when all logical path resources are occupied within a storage control unit.

4. The method of claim 1 wherein:

the determining whether to perform a logical path replacement operation is performed within a storage control unit.

5. The method of claim 1 wherein:

the logical path replaceable notification prevents other hosts from removing the logical path.

6. The method of claim 1 further comprising:

generating a host notification of logical path removal in response to replacing the logical path resources.

7. The method of claim 6 wherein:

the host notification of logical path removal provides a state change notification to the host; and

the host performs a test initialization operation to determine which logical paths are no longer established in response to the state change notification.

8. A system comprising:

a processor; and

,

a computer-usable medium embodying computer program code, the computer program code comprising instructions executable by the processor and configured for;

sending, by a host to a storage controller, a logical path replaceable notification to a logical path resource, the logical path replaceable notification indicating the logical path resource may be replaced by an owner host;

determining whether to perform a logical path replacement operation; and

performing a logical path replacement operation on the logical path having the logical path replaceable notification, the logical path replacement operation dynamically replacing the logical path resource with another logical path resource.

9. The system of claim 8, wherein

the performing a logical path replacement operation occurs in response to an establish logical path operation.

10. The system of claim 8, wherein

the performing a logical path replacement operation occurs when all logical path resources are occupied within a storage control unit.

11. The system of claim 8, wherein

the determining whether to perform a logical path replacement operation is performed within a storage control unit.

12. The system of claim 8, wherein

the logical path replaceable notification prevents other hosts from removing the logical path.

13. The system of claim 8, wherein the computer program code further comprises instructions executable by the processor and configured for:

generating a host notification of logical path removal in response to replacing the logical path resources.

14. The system of claim 13 wherein:

the host notification of logical path removal provides a state change notification to the host; and

the host performs a test initialization operation to determine which logical paths are no longer established in response to the state change notification.

15. A computer-usable medium embodying computer program code, the computer program code comprising computer executable instructions configured for:

sending, by a host to a storage controller, a logical path replaceable notification to a logical path resource, the logical path replaceable notification indicating the logical path resource may be replaced by an owner host;

determining whether to perform a logical path replacement operation; and

performing a logical path replacement operation on the logical path having the logical path replaceable notification, the logical path replacement operation dynamically replacing the logical path resource with another logical path resource.

16. The computer-usable medium embodying computer program code of claim 15, wherein

the performing a logical path replacement operation occurs in response to an establish logical path operation.

17. The computer-usable medium embodying computer program code of claim 15, wherein

the performing a logical path replacement operation occurs when all logical path resources are occupied within a storage control unit.

18. The computer-usable medium embodying computer program code of claim 15, wherein

the determining whether to perform a logical path replacement operation is performed within a storage control unit.

19. The computer-usable medium embodying computer program code of claim 15, wherein

the logical path replaceable notification prevents other hosts from removing the logical path.

20. The computer-usable medium embodying computer program code of claim 15, wherein the computer program code further comprises instructions executable by the processor and configured for:

generating a host notification of logical path removal in response to replacing the logical path resources.

21. The computer-usable medium embodying computer program code of claim 20 wherein:

the host notification of logical path removal provides a state change notification to the host; and

the host performs a test initialization operation to determine which logical paths are no longer established in response to the state change notification.