Method and system for replicating data in a distributed computer environment

• US 6,529,960 B2
• Filed: 06/29/2001
• Issued: 03/04/2003
• Est. Priority Date: 09/24/1998
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Shaheen, Amal Ahmed, Chao, Ching-Yun, Hough, Roger Eldred
• Primary Examiner(s): Geckil, Mehmet B.
• Application Number:
  US09/896,393
• Publication Number:
  US 20010037398A1
• Time in Patent Office: 613 Days
• Field of Search: 709/238, 709/246, 709/248, 709/201, 709/224, 709/242, 707/203, 707/204, 707/201, 707/8, 707/10, 707/104, 370/216, 370/312, 370/242, 370/394, 370/351, 370/401, 370/409, 370/911
• US Class Current: 709/238
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 1/187 Details of sliding window management
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 2001/0093 Point-to-multipoint
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: Y10S 707/99952 Coherency, e.g. same view to multiple users
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99954 Version management

Abstract

A method for replicating data in a distributed computer environment wherein a plurality of servers are configured about one or more central hubs in a hub and spoke arrangement. In each of a plurality of originating nodes, updates and associated origination sequence numbers are sent to the central hub. The hub sends updates and associated distribution sequence numbers to the plurality of originating nodes. The hub tracks acknowledgments sent by nodes for a destination sequence number acknowledged by all nodes. Thereafter, a highest origination sequence number is sent from the central hub back to each originating node.

Claims

1. A method for replicating data in a distributed data processing system, the method comprising:

associating a set of originating nodes with a first level central hub;

associating a set of first level central hubs with a second level central hub;

replicating a database at each originating node in the set of originating nodes;

receiving an update for replication from a given first level central hub at the second level central hub;

sending updates associated with the received update from the second level central hub to first level central hubs within the set of first level central hubs; and

tracking acknowledgments sent by first level central hubs to the second level central hub.

2. The method of claim 1 wherein a received update is associated with an origination sequence number.

3. The method of claim 1 wherein an update sent from the second level central hub to first level central hubs is associated with a distribution sequence number.

4. The method of claim 1 wherein an acknowledgment identifies a last in-sequence distribution sequence number processed by a respective first level central hub.

5. The method of claim 1 further comprising:

periodically sending a message to each first level central hub, wherein the message includes information identifying a highest origination sequence number acknowledged by the set of first level central hubs.

6. The method of claim 5 wherein the message further includes the highest origination sequence number associated with an update received at the second level central hub from a first level central hub.

7. An apparatus for replicating data in a distributed data processing system, the apparatus comprising:

means for associating a set of originating nodes with a first level central hub;

means for associating a set of first level central hubs with a second level central hub;

means for replicating a database at each originating node in the set of originating nodes;

means for receiving an update for replication from a given first level central hub at the second level central hub;

means for sending updates associated with the received update from the second level central hub to first level central hubs within the set of first level central hubs; and

means for tracking acknowledgments sent by first level central hubs to the second level central hub.

8. The apparatus of claim 7 wherein a received update is associated with an origination sequence number.

9. The apparatus of claim 7 wherein an update sent from the second level central hub to first level central hubs is associated with a distribution sequence number.

10. The apparatus of claim 7 wherein an acknowledgment identifies a last in-sequence distribution sequence number processed by a respective first level central hub.

11. The apparatus of claim 7 further comprising:

means for periodically sending a message to each first level central hub, wherein the message includes information identifying a highest origination sequence number acknowledged by the set of first level central hubs.

12. The apparatus of claim 11 wherein the message further includes the highest origination sequence number associated with an update received at the second level central hub from a first level central hub.

13. A computer program product on a computer readable medium for use in a data processing system for replicating data, the computer program product comprising:

instructions for associating a set of originating nodes with a first level central hub;

instructions for associating a set of first level central hubs with a second level central hub;

instructions for replicating a database at each originating node in the set of originating nodes;

instructions for receiving an update for replication from a given first level central hub at the second level central hub;

instructions for sending updates associated with the received update from the second level central hub to first level central hubs within the set of first level central hubs; and

instructions for tracking acknowledgments sent by first level central hubs to the second level central hub.

14. The computer program product of claim 13 wherein a received update is associated with an origination sequence number.

15. The computer program product of claim 13 wherein an update sent from the second level central hub to first level central hubs is associated with a distribution sequence number.

16. The computer program product of claim 13 wherein an acknowledgment identifies a last in-sequence distribution sequence number processed by a respective first level central hub.

17. The computer program product of claim 13 further comprising:

instructions for periodically sending a message to each first level central hub, wherein the message includes information identifying a highest origination sequence number acknowledged by the set of first level central hubs.

18. The computer program product of claim 17 wherein the message further includes the highest origination sequence number associated with an update received at the second level central hub from a first level central hub.