Method, system, and program for managing path groups to an input/output (I/O) device

• US 7,743,180 B2
• Filed: 08/10/2004
• Issued: 06/22/2010
• Est. Priority Date: 08/10/2004
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Clark, Brian Dow, Peterson, Beth Ann, Coronado, Juan Alonso
• Primary Examiner(s): Chen; Alan
• Assistant Examiner(s): YU, HENRY W
• Application Number:
  US10/916,186
• Publication Number:
  US 20060036782A1
• Time in Patent Office: 2,142 Days
• Field of Search: 710/38, 710/8, 710/200
• US Class Current: 710/38
• CPC Class Codes: G06F 13/385 for adaptation of a particular data processing system to different peripheral devices
• CPC Class Codes: G06F 3/0622 in relation to access
• CPC Class Codes: G06F 3/0635 by changing the path, e.g. traffic rerouting, path reconfiguration
• CPC Class Codes: G06F 3/0637 Permissions
• CPC Class Codes: G06F 3/0683 Plurality of storage devices

Abstract

Provided are a method, system, and program for managing path groups to an Input/Output (I/O) device. Indication is made of a connection path on which a processing system initially communicated an establish request to establish a connection with an I/O device, wherein attention that the processing system may own a lock for the I/O device is transmitted down the indicated connection path. A request is received from the processing system to add a path to a path group with respect to the I/O device, wherein the added path is capable of comprising the connection path the processing system used to establish the connection with the I/O device. The received path is added to the path group.

Claims

1. A method comprising:

establishing a connection with an Input/Output (I/O) device on a connection path between a host system and a control unit over a network, wherein the connection path comprises a logical path on which a connection with the I/O device was established;

issuing at least one command to the control unit to add at least one logical path between the host system and the control unit, other than the connection path, to a path group used by the host system to communicate with the I/O device, wherein the path group indicates multiple paths that extend through the network and that the host system uses to communicate with the I/O device via the control unit;

issuing at least one other command to the control unit to add the connection path to the path group; and

using one logical path in the path group, including the connection path or one logical path other than the connection path, to communicate with the I/O device, wherein when returning data from the I/O device to a request from the host, one path in the path group associated with the host and the I/O device is selected to return the data from the I/O device to the host system, wherein the host system receives attention to a lock request from the control unit on the connection path, wherein attention to the lock request is not returned by the control unit on logical paths in the path group other than the connection path.

2. The method of claim 1, further comprising:

transmitting a lock request for the I/O device;

receiving attention that the lock is available to access on the connection path to the I/O device; and

receiving data related to the I/O device on one path in the path group connecting to the I/O device after receiving the attention, wherein the path on which the data is received is capable of comprising the connection path or one logical path in the path group other than the connection path.

3. A method, comprising:

indicating a connection path on which a processing system initially communicated an establish request to a control unit over a network to establish a connection with an I/O device;

returning attention that the processing system may own a lock for the I/O device down the indicated connection path;

receiving at least one request from the processing system to add at least one logical requested path to a path group with respect to the I/O device, other than the connection path;

receiving at least one other request to add the connection path to the path group; and

adding the requested paths to the path group, wherein the path group includes the connection path and paths other than a connection path on which the connection to the I/O device was established, wherein attention to a lock request to the processing system is limited to being returned on the connection path, wherein attention to the lock request is not returned on logical paths in the path group other than the connection path.

4. The method of claim 3, further comprising:

determining one path in the path group to use to return data to the processing system concerning the I/O device associated with the path group, wherein the determined path is capable of comprising the connection path on which the connection between the processing system and the I/O device was established; and

using the determined path to return data to the processing system concerning the I/O device.

5. The method of claim 3, wherein the attention returned on the indicated connection path to the processing system signals the processing system that the processing system may own the lock in response to the lock for the I/O device becoming available;

and

receiving and transmitting messages with the processing system concerning the I/O device on any path in the path group, including the connection path used to establish the connection with the I/O device.

6. The method of claim 3, wherein the paths on which the processing system communicates comprise logical paths.

7. A system in communication with a control unit over a network, wherein the control unit manages access to at least one Input/Output (I/O) device, comprising:

circuitry enabled to perform;

establishing a connection with an Input/Output (I/O) device on a connection path to a control unit over a network, wherein the connection path comprises a logical path on which a connection with the I/O device was established;

issuing at least one command to the control unit to add at least one logical path to the control unit, other than the connection path, to a path group used to communicate with the I/O device, wherein the path group indicates multiple paths that extend through the network used to communicate with the I/O device via the control unit;

issuing at least one other command to the control unit to add the connection path to the path group; and

using one logical path in the path group, including the connection path or one logical path other than the connection path, to communicate with the I/O device, wherein when receiving data from the I/O device to a request, one path in the path group associated with the I/O device is used to receive the data from the I/O device, wherein attention to a lock request is received from the control unit on the connection path, wherein attention to the lock request is not received from the control unit on logical paths in the path group other than the connection path.

8. The system of claim 7, wherein the circuitry is further enabled to perform:

transmitting a lock request for the I/O device;

receiving attention that the lock is available to access on the connection path to the I/O device; and

receiving data related to the I/O device on one path in the path group connecting to the I/O device after receiving the attention, wherein the path on which the data is received is capable of comprising the connection path or one logical path in the path group other than the connection path.

9. A system in communication with a processing system over paths in a network and at least one Input/Output (I/O) device, comprising:

a computer readable storage medium;

circuitry in communication with the computer readable storage medium and enabled to perform;

indicating in the computer readable storage medium a connection path on which the processing system initially communicated an establish request over a network to establish a connection with an I/O device;

returning attention that the processing system may own a lock for the I/O device down the indicated connection path;

receiving at least one request from the processing system to add at least one logical requested path to a path group with respect to the I/O device, other than the connection path;

receiving at least one other request to add the connection path to the path group; and

adding the requested paths to the path group, wherein the path group includes the connection path and paths other than the connection path on which the connection to the I/O device was established, wherein attention to a lock request to the processing system is limited to being returned on the connection path, wherein attention to the lock request is not returned on logical paths in the path group other than the connection path.

10. The system of claim 9, wherein the circuitry is further enabled to perform:

determining one path in the path group to use to return data to the processing system concerning the I/O device associated with the path group, wherein the determined path is capable of comprising the connection path on which the connection between the processing system and I/O device was established; and

using the determined path to return data to the processing system concerning the I/O device.

11. The system of claim 9, wherein the circuitry is further enabled to perform:

returning attention on the indicated connection path to the processing system to signal the processing system that the processing system may own the lock in response to the lock for the I/O device becoming available; and

receiving and transmitting messages with the processing system concerning the I/O device on any path in the path group, including the connection path used to establish the connection with the I/O device.

12. The system of claim 9, wherein the paths on which the processing system communicates comprise logical paths.

13. An article of manufacture comprising a computer readable storage medium having code executed to communicate with a control unit over a network managing access to at least one Input/Output (I/O) device, wherein the code is executed to further perform operations, the operations comprising:

establishing a connection with an Input/Output (I/O) device on a connection path to the control unit over a network, wherein the connection path comprises a logical path on which a connection with the I/O device was established;

issuing at least one command to the control unit to add at least one logical path to the control unit, other than the connection path, to a path group used to communicate with the I/O device, wherein the path group indicates multiple paths that extend through the network used to communicate with the I/O device via the control unit;

issuing at least one other command to the control unit to add the connection path to the path group; and

using one logical path in the path group, including the connection path or one logical path other than the connection path, to communicate with the I/O device, wherein when receiving data from the I/O device to a request, one path in the path group associated with the I/O device is used to return the data from the I/O device, wherein attention to a lock request from the control unit is received on the connection path, wherein attention to the lock request is not received from the control unit on logical paths in the path group other than the connection path.

14. The article of manufacture of claim 13, wherein the operations further comprise:

transmitting a lock request for the I/O device;

receiving attention that the lock is available to access on the connection path to the I/O device; and

receiving data related to the I/O device on one path in the path group connecting to the I/O device after receiving the attention, wherein the path on which the data is received is capable of comprising the connection path or one logical path in the path group other than the connection path.

15. An article of manufacture comprising a computer readable storage medium having code executed to communicate with a network, a processing system and I/O devices, wherein the code is executed to perform operations, the operations comprising:

indicating in the computer readable storage medium a connection path on which the processing system initially communicated an establish request over the network to establish a connection with the I/O device;

returning attention that the processing system may own a lock for the I/O device down the indicated connection path;

receiving at least one request from the processing system to add at least one logical requested path to a path group with respect to the I/O device, other than the connection path receiving at least one other request to add the connection path to the path group; and

adding the requested paths to the path group, wherein the path group includes the connection path and paths other than the connection path on which the connection to the I/O device was established, wherein attention to a lock request to the processing system is limited to being returned on the connection path, wherein attention to the lock request is not returned on logical paths in the path group other than the connection path.

16. The article of manufacture of claim 15, wherein the operations further comprise:

determining one path in the path group to use to return data to the processing system concerning the I/O device associated with the path group, wherein the determined path is capable of comprising the connection path on which the connection between the processing system and I/O device was established; and

using the determined path to return data to the processing system concerning the I/O device.

17. The article of manufacture of claim 15, wherein the operations further comprise:

returning attention on the indicated connection path to the processing system to signal the processing system that the processing system may own the lock in response to the lock for the I/O device becoming available; and

receiving and transmitting messages with the processing system concerning the I/O device on any path in the path group, including the connection path used to establish the connection with the I/O device.

18. The article of manufacture of claim 15, wherein the paths on which the processing system communicates comprise logical paths.