Failover Data Replication to a Preferred List of Instances

• US 20130031403A1
• Filed: 07/28/2011
• Published: 01/31/2013
• Est. Priority Date: 07/28/2011
• Status: Active Grant

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: Oracle International Corporation (Oracle Corporation)
• Inventors: Ganapathy, Shreedhar, Mordani, Rajiv P., Kannan, Mahesh, Saxena, Kshitiz
• Granted Patent: US 8,954,786 B2
• Time in Patent Office: Days
• US Class Current: 714/4.11
• CPC Class Codes: G06F 11/1658 Data re-synchronization of a redundant component, or initial sync of replacement, additional or spare unit
• CPC Class Codes: G06F 11/2028 eliminating a faulty processor or activating a spare
• CPC Class Codes: G06F 11/2041 with more than one idle spare processing component
• CPC Class Codes: H04L 67/56 Provisioning of proxy services store-and-forward switching systems in data switching networks H04L12/54

Abstract

A method, system, and medium are disclosed for performing transparent failover in a cluster server system. The cluster includes a plurality of servers. In servicing a client request, a primary server replicates session data for the client into memory space of one or more backup servers. The primary server sends a response to the client, wherein the response includes an indication of the one or more backup servers. When the client sends a subsequent request, it includes an indication of the backup servers. If the primary server is unavailable, the cluster determines a recovery server from among the backup servers indicated by the request. The chosen recovery server would then service the request.

Claims

1. A computer-implemented method, comprising:

a cluster of servers servicing a client request, wherein the servicing includes;

a primary server of the servers replicating session data for the client into memory space of one or more backup servers of the servers; and

the primary server sending a response to the request, wherein the response includes an indication of the one or more backup servers.

2. The method of claim 1, further comprising:

the cluster receiving a subsequent request from the client, wherein the subsequent request includes an indication of the one or more backup servers;

in response to determining that the primary server is unavailable to service the subsequent request, determining a recovery server from among the one or more backup servers indicated by the subsequent request; and

the recovery server servicing the subsequent request.

3. The method of claim 2, wherein the subsequent request encodes the indication of the one or more backup servers in a URL in the response or encodes the indication of the one or more backup servers in a cookie.

4. The method of claim 2, wherein a load balancer performs the determining the recovery server from among the backup servers.

5. The method of claim 2, wherein one of the cluster of servers performs the determining the recovery server from among the backup servers.

6. The method of claim 2, further comprising:

automatically routing one or more additional client requests to the recovery server, wherein the additional requests are received after the subsequent request.

7. The method of claim 1, wherein the replicating is performed using a replication software layer.

8. The method of claim 7, wherein the replication software layer exposes a programmatic interface for storing, retrieving, updating, or deleting the replicated session data.

9. The method of claim 7, wherein the replication software layer is implemented using a plurality of replication modules, wherein each of the replication modules executes on a respective server instance.

10. The method of claim 7, wherein the replication software layer is implemented using a second set of servers separate from the primary servers and backup servers.

11. The method of claim 1, wherein the replicating comprises:

determining the one or more backup servers by calculating a function of;

a unique session identifier for the client and a view of the cluster.

12. The method of claim 1, wherein the indication of the one or more backup servers included in the response is stored in a cookie that the client is configured to return in a subsequent request.

13. A system comprising:

a cluster of computers executing a plurality of servers, wherein the servers comprise a primary server configured to serve a client request, wherein servicing the client request includes;

replicating session data for the client into memory space of one or more backup servers of the plurality of servers; and

sending a response to the client request, wherein the response includes an indication of the one or more backup servers.

14. The system of claim 13, wherein the cluster of computers is further configured to:

receive a subsequent request from the client wherein the subsequent request includes an indication of the one or more backup servers;

in response to determining that the primary server is unavailable to service the subsequent request, determine a recovery server from among the one or more backup servers indicated by the subsequent request; and

service the subsequent request using the recovery server.

15. The system of claim 14, wherein the indication of the one or more backup servers included in the subsequent request is encoded in a URL in the response or encodes the indication of the one or more backup servers in a cookie.

16. The system of claim 14, wherein the cluster further executes a load balancer, wherein the load balancer is configured to perform the determining the recovery server from among the one or more backup servers.

17. The system of claim 13, wherein the replicating is performed using a replication software layer that exposes a programmatic interface for storing, retrieving, updating, or deleting the replicated session data.

18. The system of claim 13, wherein the replicating comprises:

determining the one or more backup servers by calculating a function of;

a unique session identifier for the client and a view of the cluster.

19. A non-transitory storage medium storing program instructions executable by a computer to implement:

a server configured to service a request from a client, wherein the servicing comprises;

replicating session data for the client into memory space of one or more backup servers; and

sending a response to the request, wherein the response includes an indication of the one or more backup servers.

20. The storage medium of claim 19, wherein the client is configured to respond to receiving the indication of the one or more backup servers by including an indication of the one or more backup servers in a subsequent request.