Fault Recovery in Concurrent Queue Management Systems

• US 20100229025A1
• Filed: 05/20/2010
• Published: 09/09/2010
• Est. Priority Date: 06/02/2005
• Status: Active Grant

• Current Assignee: Avaya Incorporated
• Original Assignee: Avaya Incorporated
• Inventors: Qutub, Sami, Sitkowski, Rafal
• Granted Patent: US 7,925,921 B2
• Time in Patent Office: Days
• US Class Current: 714/2
• CPC Class Codes: G06F 11/1479 Generic software techniques for error detection or fault masking
• CPC Class Codes: G06F 11/3006 where the computing system is distributed, e.g. networked systems, clusters, multiprocessor systems multiprogramming arrangements G06F9/46; allocation of resources G06F9/50
• CPC Class Codes: G06F 11/3055 Monitoring arrangements for monitoring the status of the computing system or of the computing system component, e.g. monitoring if the computing system is on, off, available, not available error or fault processing without redundancy G06F11/0703; error detection or correction by redundancy in data representation G06F11/08; error detection or correction by redundancy in operation G06F11/14; error detection or correction by redundancy in hardware G06F11/16
• CPC Class Codes: H04L 41/0654 using network fault recovery ring fault isolation or reconfiguration in loop networks without recovery actions by a network management system H04L12/437

Abstract

A method for fault tolerance and fault recovery in multiprocessor systems that concurrently manage queues is disclosed. The illustrative embodiment comprises a plurality of servers, a queue of jobs to be assigned to the servers, and two queue managers—a primary unit and a secondary unit—such that the secondary fills in for the primary unit while the primary unit is down. The illustrative embodiment provides for smooth transitions from the normal state into the failure state and back into the normal state without losing jobs or violating the queue discipline of the system.

Claims

1. A method comprising:

recovering a queue manager from a failure, wherein said queue manager is for assigning jobs to a server; and

inferring that a queue external to said queue manager does not contain any jobs that arrived prior to the recovery of said queue manager from said failure.

2. The method of claim 1 wherein the inference is performed without knowledge of the contents of said queue.

3. The method of claim 2 wherein the inference occurs if, and only if, said server is idle for more than N seconds, wherein N is a positive real number.

4. The method of claim 1 further comprising:

receiving a job at said queue manager after the recovery of said queue manager from said failure; and

refraining from assigning said job until after the inference is made.

5. The method of claim 1 wherein during said failure another queue manager assigns one or more jobs to said server.

6. The method of claim 5 wherein said queue manager and said other queue manager employ different queue disciplines.

7. The method of claim 5 wherein said queue manager provides more functionality than said other queue manager.

8. The method of claim 5 wherein said other queue manager provides more functionality than said queue manager.

9. The method of claim 5 wherein said queue manager is hardware-based and said other queue manager is software-based.

10. The method of claim 5 wherein said queue manager is software-based and said other queue manager is hardware-based.

11. The method of claim 5 wherein at least one of said one or more jobs is a telephone call.

12. The method of claim 5 wherein at least one of said one or more jobs is an Internet Protocol packet.

13. The method of claim 1 wherein at least one of said jobs is a telephone call.

14. The method of claim 1 wherein at least one of said jobs is an Internet Protocol packet.