Persistent reservation IO barriers

• US 20040153711A1
• Filed: 08/01/2003
• Published: 08/05/2004
• Est. Priority Date: 04/11/2000
• Status: Active Grant

• Current Assignee: Valtrus Innovations Limited (f/k/a Dolya Holdco 9 Limited) (Key Patent Innovations Limited)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Brunelle, Alan David, Wahlstrom, Per Olov
• Granted Patent: US 7,346,801 B2
• Time in Patent Office: Days
• US Class Current: 714/4
• CPC Class Codes: G06F 2003/0697 device management, e.g. handlers, drivers, I/O schedulers
• CPC Class Codes: G06F 3/0601 Interfaces specially adapted for storage systems
• CPC Class Codes: G06F 9/468 Specific access rights for resources, e.g. using capability register
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: Y10S 707/99939 Privileged access

Abstract

A method for sharing a storage device amongst a plurality of computers while providing data integrity in the storage device is presented. A computer is registered for a reserved access type with the storage device by storing a computer identifier in the storage device. Access to the storage device is provided to the registered computer dependent on the registered computer'"'"'s stored identifier and the reserved access type. Upon loss of knowledge of the stored identifier in the shared storage device by the registered computer, the computer replaces the previous identifier for the computer stored in the shared storage device with a new identifier. The registered computer may be a currently registered computer or a previously registered computer.

Claims

1. A method for sharing a storage device among a plurality of computers while providing data integrity in the storage device, the method comprising the steps of:

registering the computer with the storage device by storing in the storage device a computer identifier associated with a reserved access type in the storage device; and

upon loss of a knowledge of the stored identifier in the shared storage device by the registered computer, replacing the identifier for the registered computer stored in the shared storage device with a new identifier for the registered computer.

2. The method as claimed in claim 1 wherein the registered computer is a currently registered computer.

3. The method as claimed in claim 1 wherein the registered computer is a previously registered computer.

4. An apparatus for sharing a storage device among a plurality of computers while providing data integrity in the storage device, the apparatus comprising:

a register routine which registers a computer with a storage device by storing in the storage device a computer identifier associated with a reserved access type in the storage device and upon detection of loss of knowledge of the stored computer identifier in the shared device by the registered computer replaces the identifier for the registered computer stored in the shared storage device with a new identifier for the registered computer.

5. An apparatus as claimed in claim 4 wherein the registered computer is a currently registered computer.

6. An apparatus as claimed in claim 4 wherein the registered computer is a previously registered computer.

7. An apparatus for sharing a storage device among a plurality of computers while providing data integrity in the storage device, the apparatus comprising:

means for registering the computer with a shared storage device by storing in the storage device an identifier associated with a reserved access type for the shared storage device; and

upon detection of loss of knowledge of the stored identifier in the shared device by the registered computer, means for replacing the identifier for the registered computer stored in the shared storage device with a new identifier for the registered computer.

8. An apparatus as claimed in claim 7 wherein the registered computer is a currently registered computer.

9. An apparatus as claimed in claim 7 wherein the registered computer is a previously registered computer.

10. An apparatus as claimed in claim 7 wherein the identifier for each computer is unique.

11. A computer system comprising:

a central processing unit connected to a memory bus by a system bus;

an I/O system, connected to the system bus by a bus interface; and

a routine for providing data integrity in a storage device shared by the computer system with another computer system, the routine;

registering the computer with the shared storage device by storing in the storage device an identifier associated with a reserved access type for the shared storage device; and

upon loss of a knowledge of the stored identifier in the shared storage device by the registered computer, replacing the identifier for the registered computer stored in the shared storage device with a new identifier for the registered computer.

12. A computer program product for providing data integrity in a storage device shared by a plurality of computers, the computer program product comprising a computer usable medium having computer readable program code thereon, including program code which:

registers the computer with the shared storage device by storing in the storage device an identifier associated with a reserved access type for the shared storage device; and

upon loss of a knowledge of the stored identifier in the shared storage device by the registered computer, replaces the identifier for the registered computer stored in the shared storage device with a new identifier for the registered computer.