APPARATUS AND METHOD TO ADJUST A MULTI-PATH DEVICE RESERVATION

• US 20110082951A1
• Filed: 10/07/2009
• Published: 04/07/2011
• Est. Priority Date: 10/07/2009
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: RIPBERGER, RICHARD ANTHONY, KALOS, MATTHEW JOSEPH, HARDY, CLINT ALAN
• Granted Patent: US 8,417,849 B2
• Time in Patent Office: Days
• US Class Current: 710/38
• CPC Class Codes: G06F 11/201 between storage system components
• CPC Class Codes: G06F 3/0617 in relation to availability

Abstract

A method to adjust a multi-path device reservation by supplying a computing device and a storage controller interconnected with a communication link. The method further reserves a data storage device in communication with the storage controller, where that data storage device reservation is held by a first communication path group comprising a first plurality of communication paths configured in the communication link. If the method detects a failed communication path configured in the first communication path group, the method configures a second communication path group by removing the failed communication path from the first communication path group, wherein the second communication path group maintains the data storage device reservation.

Claims

1. A method to adjust a multi-path device reservation, comprising:

supplying a computing device and a storage controller interconnected with a communication link;

reserving a data storage device in communication with said storage controller, wherein said data storage device reservation is held by a first communication path group comprising a first plurality of communication paths configured in said communication link;

detecting a failed communication path configured in said first communication path group;

configuring a second communication path group by removing said failed communication path from said first communication path group, wherein said second communication path group maintains said data storage device reservation.

2. The method of claim 1, further comprising issuing a remove port command.

3. The method of claim 2, wherein said issuing step comprises:

forming a Set-Path-group-ID (“

SPID”

) command comprising 12 bytes of data including a one byte function code and an 11 byte communication path id, wherein said one byte function code comprises a 2 bit group code;

setting said 2 bit group code to indicate that said SPID command comprises said remove port command.

4. The method of claim 2, wherein:

said storage controller comprises a plurality of control unit ports;

said first plurality of communication paths interconnect with said storage controller using said plurality of control unit ports;

said failed communication path interconnects with said storage controller using a first control unit port, wherein said first control unit port is one of said plurality of control unit ports.

5. The method of claim 4, wherein said issuing step further comprises generating a remove port command reciting an interface_id specifying said first control unit port, wherein the method further comprises issuing said remove port command to said storage controller using any of said plurality of control unit ports except said first control unit port.

6. The method of claim 5, further comprising:

generating a two byte interface ID that is data storage device independent, and that uniquely identifies a control unit port that is to be remove from the communication path group by the remove port command;

verifying a communication path group id;

removing communication paths to said reserved data storage device that utilize the first control unit port.

7. The method of claim 6, further comprising:

determining if any of said first communication paths utilize said first control unit port;

operative if none of said first communication paths utilize said first control unit port;

taking no action;

maintaining said device reservation with said first communication path group.

8. The method of claim 6, further comprising

operative if any of said first communication paths utilize said first control unit port, configuring a second communications path group by removing paths that utilize said first control unit port.

9. The method of claim 6, further comprising:

determining if all communication paths have been removed from said reserved device;

operative if all communication paths have been removed from said reserved device, maintaining said device reservation with a communication path that issued said remove port command.

10. A computing device interconnected with a storage controller by a communication link and comprising a computer readable medium having computer readable program code disposed therein to adjust a multi-path data storage device reservation, the computer readable program code comprising a series of computer readable program steps to effect:

reserving a data storage device in communication with said article of manufacture, wherein said data storage device reservation is held by a first communication path group configured in said communication link, wherein said first communication path group comprises a first plurality of communication paths;

detecting a failed communication path configured in said first communication path group;

configuring a second communication path group by removing said failed communication path from said first communication path group, wherein said second communication path group maintains said data storage device reservation.

11. The computing device of claim 10, wherein said computer readable program code further comprises a series of computer readable program steps to effect issuing a remove port command.

12. The computing device of claim 11, wherein said computer readable program code to generate a remove port command further comprises a series of computer readable program steps to effect:

forming a Set-Path-group-ID (“

SPID”

) command comprising 12 bytes of data including a one byte function code and an 11 byte communication path id, wherein said one byte function code comprises a 2 bit group code;

setting said 2 bit group code to indicate that said SPID command comprises said remove port command.

13. The computing device of claim 11, wherein:

said storage controller comprises a plurality of control unit ports;

said first plurality of communication paths interconnect with said storage controller using said plurality of control unit ports;

said failed communication path interconnects with said storage controller using a first control unit port, wherein said first control unit port is one of said plurality of control unit ports.

14. The computing device of claim 13, wherein said computer readable program code to issue a remove port command further comprises a series of computer readable program steps to effect:

generating a remove port command reciting an interface_id identifying said first control unit port;

issuing said remove port command to said storage controller using any of said plurality of control unit ports except said first control unit port.

15. A storage controller comprising a plurality of control unit ports and interconnected with a computing device by a communication link and comprising a computer readable medium having computer readable program code disposed therein to adjust a multi-path data storage device reservation, the computer readable program code comprising a series of computer readable program steps to effect:

reserving a data storage device in communication with said article of manufacture, wherein said data storage device reservation is held by a first communication path group configured in said communication link, wherein said first communication path group comprises a first plurality of communication paths;

receiving a remove port command reciting an interface_id identifying a first control unit port, wherein said first control unit port is one of said plurality of control unit ports.

16. The storage controller of claim 15, wherein said computer readable program code further comprises a series of computer readable program steps to effect:

generating a two byte interface ID that is data storage device independent, and that uniquely identifies a control unit port that received the remove port command;

verifying the communication path group id;

removing communication paths to said reserved data storage device that utilize the first control unit port.

17. The storage controller of claim 16, said computer readable program code further comprising a series of computer readable program steps to effect:

determining if any of said first communication paths utilize said first control unit port;

operative if none of said first communication paths utilize said first control unit port;

taking no action;

maintaining said device reservation with said first communication path group.

18. The storage controller of claim 17, said computer readable program code further comprising a series of computer readable program steps to effect:

operative if any of said first communication paths utilize said first control unit port, configuring a second communications path group by removing paths that utilize said first control unit port.

19. The storage controller of claim 16, said computer readable program code further comprising a series of computer readable program steps to effect:

determining if all communication paths have been removed from said reserved device;

operative if all communication paths have been removed from said reserved device, maintaining said device reservation with a communication path that issued said remove port command.

20. A computer program product encoded in a computer readable medium and useable with a programmable computer processor to adjust a multi-path data storage device reservation disposed in a storage system comprising a computing device and a storage controller interconnected with a communication link, the computer program product comprising:

computer readable program code which causes said programmable processor to reserve a data storage device in communication with said storage controller, wherein said data storage device reservation is held by a first communication path group comprising a first plurality of communication paths configured in said communication link;

computer readable program code which causes said programmable processor to detect a failed communication path configured in said first communication path group;

computer readable program code which causes said programmable processor to configure a second communication path group by removing said failed communication path from said first communication path group, wherein said second communication path group maintains said data storage device reservation.

21. The computer program product of claim 20, further comprising computer readable program code which causes said programmable processor to issue a remove port command.

22. The computer program product of claim 21, wherein said computer readable program code which causes said programmable processor to issue a remove port command comprises:

computer readable program code which causes said programmable processor to form a Set-Path-group-ID (“

SPID”

) command comprising 12 bytes of data including a one byte function code and an 11 byte communication path id, wherein said one byte function code comprises a 2 bit group code;

computer readable program code which causes said programmable processor to set said 2 bit group code to indicate that said SPID command comprises said remove port command.

23. The computer program product of claim 22, wherein:

said storage controller comprises a plurality of control unit ports;

said first plurality of communication paths interconnect with said storage controller using said plurality of control unit ports;

said failed communication path interconnects with said storage controller using a first control unit port, wherein said first control unit port is one of said plurality of control unit ports.

24. The computer program product of claim 23, wherein said computer readable program code which causes said programmable processor to generate a remove port command further comprises computer readable program code which causes said programmable processor to generate a remove port command reciting an interface_id identifying said first control unit port, further comprising computer readable program code which causes said programmable processor to issue said remove port command to said storage controller using any of said plurality of control unit ports except said first control unit port.

25. The computer program product of claim 24, further comprising:

computer readable program code which causes said programmable processor to generate a two byte interface ID that is data storage device independent, and that uniquely identifies a control unit port that is to be remove from the communication path group by the remove port command;

computer readable program code which causes said programmable processor to verify the communication path group id;

computer readable program code which causes said programmable processor to remove communication paths to said reserved data storage device that utilize the first control unit port.