Path control device, system, cluster, cluster system, method and computer readable medium embodying program

• US 20070022227A1
• Filed: 06/16/2006
• Published: 01/25/2007
• Est. Priority Date: 07/22/2005
• Status: Abandoned Application

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Miki, Kenichi
• Application Number:
  US11/453,797
• Publication Number:
  US 20070022227A1
• Time in Patent Office: Days
• US Class Current: 710/38
• CPC Class Codes: G06F 11/201 between storage system components
• CPC Class Codes: G06F 11/2089 Redundant storage control functionality

Abstract

A path control device that controls first and second paths for accessing a peripheral subsystem, includes a command substituting unit that substitutes a first reserve command that allows an access through the first path, with a second reserve command that allows both of accesses through both of the first path and the second path.

Claims

1. A path control device that controls first and second paths for accessing a peripheral subsystem, comprising:

a command substituting unit that substitutes a first reserve command that allows an access through said first path, with a second reserve command that allows accesses through both of said first path and said second path.

2. The path control device according to claim 1, further comprising:

a command acquiring unit that acquires said first reserve command; and

a command issuing unit that issues said second reserve command to said peripheral subsystem.

3. The path control device according to claim 1, wherein said second reserve command includes information related to said first path.

4. The path control device according to claim 2, wherein said command acquiring unit includes a function of acquiring at least one command of:

a release command that releases a reserve of said second path;

a reset command that cancels said reserve of said second path; and

a compulsory release command that compulsorily releases said reserve of said second path.

5. The path control device according to claim 4, wherein said command substituting unit substitutes said at least one command of said release command, said reset command and said compulsory command by a command that denies an access through only said second path,

wherein said command issuing unit issues said command.

6. The path control device according to claim 4, wherein said at least one command includes information related to said second path.

7. A system, comprising:

a host computer that includes said path control device according to claim 1;

and

said peripheral subsystem according to claim 1.

8. The system according to claim 7, wherein said peripheral subsystem uses an SCSI (Small Computer System Interface) protocol.

9. The system according to claim 7, wherein said peripheral subsystem includes a disk array subsystem.

10. A cluster, comprising:

host computers, each of said host computers including said path control device according to claim 1.

11. A cluster system, comprising:

said cluster according to claim 10;

said peripheral subsystem; and

a switch that connects one of said host computers to said peripheral subsystem with respect to said first path of said each host computer.

12. A method of controlling first and second paths for accessing a peripheral subsystem, comprising:

substituting a first reserve command that allows an access through said first path by a second reserve command that allows accesses through both of said first path and said second path.

13. The method according to claim 12, further comprising:

acquiring said first reserve command; and

issuing said second reserve command to said peripheral subsystem.

14. The method according to claim 12, wherein said second reserve command includes information related to said first path.

15. The method according to claim 13, further comprising:

acquiring at least one of;

a release command that releases a reserve of said second path;

a reset command that cancels said reserve of said second path; and

a compulsory release command that compulsorily releases said reserve of said second path.

16. The method according to claim 15, further comprising:

substituting said at least one command of said release command, said reset command and said compulsory command by a command that denies an access only through said second path; and

issuing said command.

17. The method according to claim 16, wherein said at least one command includes information related to said second path.

18. A computer readable medium embodying a program, said program causing a path control device to perform the method of claim 12.