Urgent replication facility

• US 20020144252A1
• Filed: 05/23/2002
• Published: 10/03/2002
• Est. Priority Date: 07/01/1996
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Contorer, Aaron M., Straube, Dave D., Miller, Arnold S., Misra, Pradyumna K., Raman, Balan S., Seaman, Michael R.C.
• Granted Patent: US 7,200,847 B2
• Time in Patent Office: Days
• US Class Current: 717/168
• CPC Class Codes: G06F 16/1844 Management specifically adapted to replicated file systems
• CPC Class Codes: G06F 9/54 Interprogram communication

Abstract

A system and method for expediting the replication of at least one specified object to a replica in a distributed computer system. A source object of a source replica determines that it has an urgent change to propagate through the distributed system, and informs a replication facility at the source replica of the urgent change. The facility extracts, or is provided with, the change information from that object, and the source replica communicates information representative of the change to a destination replica. A replication facility at the destination replica provides the change information to a destination replica object, which uses the information to make itself consistent with the source replica object.

Claims

1. In a distributed computer system, a method of expediting the replication of at least one specified object to a replica in the system, comprising the steps of, receiving information at a source indicating that an object of said source has changed, extracting change information from the object representative of the change thereto, transmitting information to a destination replica corresponding to the change, receiving the transmitted information at the destination replica, extracting the change information from the received information, and providing the change information to a replica object of the destination.

2. The method of claim 1 further comprising the step of applying the change information to the replica object at the destination such that the replica object at the destination is consistent with the changed object at the source.

3. The method of claim 1 wherein the step of receiving information at a source indicating that an object of said source has changed includes the step of placing a call from the object to a selected function.

4. The method of claim 1 wherein the step of extracting change information from the object includes the step of duplicating the entire object, and the step of transmitting information to a destination replica includes the step of transmitting the entire object.

5. The method of claim 1 wherein the step of extracting information comprises the step of generating differencing information.

6. The method of claim 1 further comprising the step of delaying for a time interval before the step of transmitting information to the destination replica corresponding to the change.

7. In a system of distributed computers, a system for expediting the replication of an object which has changed at a source node to a counterpart object at a destination node, comprising, signaling means for generating a signal at the source indicating that the object at the source has changed, a control means connected to the signaling means for receiving the signal generated thereby, the control means communicating with the object to extract information from the changed object representative of the change, a data communication mechanism at the source node connected to a data communication mechanism at the destination node for communicating information representative of the change to the object from the source node to the destination node, and means at the destination node for applying the received change information to the counterpart object at the destination such that the counterpart object at the destination node is consistent with the changed object at the source node.

8. In a distributed computer system, a method of replicating at least one specified object to a replica in the system, comprising the steps of, communicating a request from a destination node to a source node to replicate objects which have changed at the source node, receiving the request at the source node and obtaining information from at least one object therein which has changed, the information representative of the change to that object, transmitting information to a destination replica corresponding to the change, receiving the transmitted information at the destination replica, extracting the change information from the received information, and providing the change information to a replica object of the destination.

9. The method of claim 8 further comprising the step of applying the change information to the replica object at the destination such that the replica object at the destination is consistent with the changed object at the source.

10. The method of claim 8 further comprising the step of communicating at least one other object which has changed from the source to the destination node.

11. The method of claim 8 wherein the step of communicating a request to replicate objects from a destination node to a source node includes the step of providing a cursor indicative of a starting point from which to replicate, and the step of obtaining information from at least one object which has changed includes the step of eliminating objects which have not changed since the starting point.

12. The method of claim 8 wherein the step of obtaining information from the object comprises the step of generating differencing information.

15. The method of claim 14 wherein the time interval is substantially zero.

18. The system of claim 17 wherein the means within the source object for recognizing a change thereto includes means for recognizing that changes thereto are either urgent or non-urgent changes, wherein urgent changes are pushed to the destination as determined by the source and non-urgent changes are pulled from the source as determined by the destination.

13. In a system of distributed computers, a system for replicating at least one object which has changed at a source node to a counterpart object at a destination node, comprising, means at the source node for extracting information from at least one changed object representative of the change thereto, a data communication mechanism at the destination node connected to a data communication mechanism at the source node for communicating a request from the destination node to replicate objects which have changed at the source node, and for communicating information from the source node to the destination node representative of the change extracted from the at least one changed object, and means at the destination node for applying the received change information to the counterpart object at the destination such that the counterpart object at the destination node is consistent with the changed object at the source node.

14. In a distributed computer system, a method of expediting the replication of at least one specified object to a replica in the system, comprising the steps of, receiving information at a source indicating that an object of said source has changed, notifying a destination replica that the object has changed, transmitting from the destination to the source a request for change information after a time interval, extracting change information at the source from the object representative of the change thereto, transmitting information from the source to the destination, the transmitted information including the extracted change information, receiving the transmitted information at the destination replica, extracting the change information from the received information, and providing the change information to a replica object of the destination.

16. In a distributed computer system having at least one source replica and one destination replica, a method of making a destination object at the destination replica consistent with a changed source object at the source replica, comprising the steps of, recognizing a change to the source object, notifying a replication facility at the source of the change, communicating information corresponding to the change to a destination replica, providing the information to the destination object, and using the information corresponding to the change to change the destination object such that the destination object becomes consistent with the source object.

17. In a distributed computer system having at least one source replica and one destination replica, a framework for making a destination object at the destination replica consistent with a changed source object at the source replica, comprising, a source replication facility at the source, means within the source object for recognizing an change thereto and for notifying the source replication facility of the change, means for communicating information to a destination replica including information corresponding to the change, a destination replication facility at the destination for providing the communicated information to the destination object, and means within the destination object for changing the destination object such that the destination object becomes consistent with the source object.