Method and apparatus for session replication and failover

• US 7,409,420 B2
• Filed: 10/31/2001
• Issued: 08/05/2008
• Est. Priority Date: 07/16/2001
• Status: Expired due to Term

• Current Assignee: Oracle International Corporation (Oracle Corporation)
• Original Assignee: BEA Systems Incorporated (Oracle Corporation)
• Inventors: Messinger, Adam, Jacobs, Dean Bernard, Pullara, Sam, Halpern, Eric M., Peddada, Prasad
• Primary Examiner(s): Cardone; Jason
• Assistant Examiner(s): Mirza; Adnan M
• Application Number:
  US10/000,708
• Publication Number:
  US 20030014480A1
• Time in Patent Office: 2,470 Days
• Field of Search: 709/213, 709/227, 709/203, 709/231, 709/230, 370/352
• US Class Current: 709/203
• CPC Class Codes: G06F 11/2028 eliminating a faulty processor or activating a spare
• CPC Class Codes: G06F 11/2035 without idle spare hardware
• CPC Class Codes: G06F 11/2046 where the redundant components share persistent storage G06F11/2043 takes precedence
• CPC Class Codes: G06F 11/2097 maintaining the standby controller/processing unit updated initialisation or re-synchronisation thereof G06F11/1658 and subgroups
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/10015 Access to distributed or replicated servers, e.g. using brokers
• CPC Class Codes: H04L 67/1008 based on parameters of servers, e.g. available memory or workload monitoring of computer activity G06F11/30
• CPC Class Codes: H04L 67/1017 based on a round robin mechanism
• CPC Class Codes: H04L 67/1021 based on client or server locations
• CPC Class Codes: H04L 67/1027 Persistence of sessions during load balancing
• CPC Class Codes: H04L 67/1031 Controlling of the operation of servers by a load balancer, e.g. adding or removing servers that serve requests
• CPC Class Codes: H04L 67/1034 Reaction to server failures by a load balancer
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A session replication system provides real-time data replication without unnecessarily slowing down the user experience. A system in accordance with the present invention may utilize a primary server to serve requests from a network client, as well as a secondary server to replicate the session information. When a request is received on the session, an attempt may be made to serve the request on the primary server. If the primary is unable to receive or respond to the request, the request may be served on the secondary application server or on a new primary server. If the secondary server receives the request, the secondary server may become the new primary server. If a new primary server is selected, the new primary may request the session information from the secondary server.

Claims

1. A system for replicating information in a client session, comprising:

a. a primary server adapted to receive a request in a client session and serve a response to that request, said primary server further adapted to store session information for that client session;

b. a secondary server adapted to receive request in a client session and serve a response to that request, said secondary server storing session information for that client session concurrently with the primary server; and

c. a web server adapted to receive a request from a client, the request containing identification information for said primary and secondary servers, the web server adapted to process the identification information and serve the process request on said primary server, the web server further adapted to serve the request on said secondary server if said primary server is unable to process the request wherein the client session information is sufficient for the secondary server to maintain the client session;

wherein the session information allows the primary or secondary server to provide client specific responses to client requests, the session information allowing the primary or secondary server to continue a previously started internet session by serving the response to the request using client session data from the session information.

2. A system according to claim 1, further comprising a database in communication with said primary and secondary servers, said database storing information useful in processing the request.

3. A system according to claim 1, wherein said primary server is further adapted to update the session information stored in said second session server each time said primary server receives a request for that client session.

4. A system according to claim 1, wherein said web server is further adapted to choose said primary server from a plurality of servers when an initial request is received for the client session and no identification information exists on the client.

5. A system according to claim 1, further comprising a cookie adapted to be stored on the client, said cookie adapted to contain the identification information for said primary and secondary servers.

6. A system according to claim 5, wherein said primary server is further adapted to generate said cookie on the client.

7. A system according to claim 1, wherein said web server further comprises a plug-in containing an algorithm to be used in choosing said primary server.

8. A system according to claim 1, wherein said web server further comprises a plug-in containing an algorithm to be used in directing the request to said primary and secondary servers.

9. A system according to claim 7, wherein said algorithm is a load-balancing algorithm.

10. A system according to claim 1, wherein said primary server is adapted to select said secondary server.

11. A system according to claim 1, wherein said primary server is adapted to start the client session when receiving an initial request from the client.

12. A system according to claim 1, wherein said secondary server is further adapted to become the new primary server if the secondary server receives a request that could not be processed by said primary server.

13. A system according to claim 12, wherein said secondary server is further adapted to select a new secondary server and send the session information to the new secondary server.

14. A system according to claim 12, wherein said web server chooses a new secondary server.

15. A system according to claim 1, wherein said secondary server is further adapted to monitor said primary server to determine if said primary server may receive requests.

16. A system according to claim 1, wherein said secondary server is further adapted to become a new primary server if said primary server is unable to receive requests.

17. A system according to claim 1, wherein one of said primary and secondary servers is selected from the group consisting of web servers, servlet engines, and enterprise Java bean engines.

21. A system according to claim 1, wherein said web server is further adapted to send requests to said primary server in batches.

18. A system for replicating information in a Java client session, comprising:

a. a primary server adapted to receive a request from a Java client in a client session and serve a response to that request, said primary server further adapted to store session information for that client session;

b. a secondary server adapted to receive request in a client session and serve a response to that request, said primary server storing session information for that client session concurrently with the primary server; and

c. a stateful session bean on the primary server used to store information for the client session and pass the identity of said primary and secondary servers back to the client wherein the client session information is sufficient for the secondary server to maintain the client session;

wherein the session information allows the primary or secondary server to provide client specific responses to client requests, the session information allowing the primary or secondary server to continue a previously started internet session by serving the response to the request using client session data from the session information.

19. A system according to claim 18, further comprising a load balancer adapted to receive a request from a client and select said primary server.

20. A system according to claim 18, wherein said primary server is adapted to maintain a persistent connection with the Java client during the client session.

22. A method for providing redundancy in a client session, comprising:

a. making a load balancing decision for an initial request from a client in a client session in order to select a primary server from a plurality of session servers;

b. serving said request on said primary server;

c. selecting a secondary server;

d. sending session information for that client session from the primary server to the secondary server; and

e. updating session information on the primary and secondary servers each time a request is received in the client session wherein the client session information is sufficient for the secondary server to maintain the client session;

wherein the session information allows the primary or secondary server to provide client specific responses to client requests, the session information allowing the primary or secondary server to continue a previously started internet session by serving the response to the request using client session data from the session information.

23. A method according to claim 22, further comprising:

storing the information in a cookie on the client.

24. A method according to claim 22, further comprising:

serving the request on the secondary server if the primary server is unable to process the request.

25. A method according to claim 24, further comprising:

selecting a new secondary server.

26. A method according to claim 22, further comprising:

serving requests to the primary server in batches.

27. A method according to claim 22, further comprising:

sending session information for that client session from the primary server to the secondary server in batches.

28. A method according to claim 22, further comprising:

storing session information in a stateful session bean.

29. A method according to claim 22, further comprising:

associating a version number with each update to the session information in response to a request.

30. A method according to claim 22, wherein sending session information for that client session from the primary server to the secondary server comprises sending a delta of information containing the changes in the session information.

31. A method according to claim 22, further comprising:

assigning the primary and secondary servers each an identification number.

32. A method according to claim 31, further comprising:

adding the identification number for the primary and secondary servers to obtain one number that describes both the primary and secondary servers.

33. A system for replicating information in a client session, comprising:

a. a plurality of session servers;

b. a primary server in said plurality of session servers, said primary server adapted to receive a request in a client session and serve a response to that request, said primary server further adapted to store session information for that client session, and adapted to generate a cookie containing information relating to said primary server and transmit the cookie to the session client;

c. a secondary server in said plurality of session servers selected by said primary server, said secondary server receiving the session information from said primary server and store the session information, the secondary server further adapted to receive a request in a client session and serve a response to that request; and

d. a web server adapted to receive a request from a client, the request containing identification information for said primary and secondary servers, the web server adapted to process the identification information and serve the process request on said primary server, the web server further adapted to serve the request on said secondary server if said primary server is unable to process the request wherein the client session information is sufficient for the secondary server to maintain the client session;

wherein the session information allows the primary or secondary server to provide client specific responses to client requests, the session information allowing the primary or secondary server to continue a previously started internet session by serving the response to the request using client session data from the session information.

34. A method for providing redundancy in a client session, comprising:

a. making a load balancing decision for an initial request from a client in a client session in order to select a primary server from a plurality of session servers;

b. serving said request on said primary server;

c. sending session information for that client session from the primary server to a secondary server selected by said primary server;

d. storing a cookie on the session client containing information identifying the primary and secondary servers; and

e. updating session information on the primary and secondary servers each time a request is received in the client session;

wherein the session information allows the primary or secondary server to provide client specific responses to client requests, the session information allowing the primary or secondary server to continue a previously started internet session by serving the response to the request using client session data from the session information.

35. A method according to claim 34, further comprising the step of reading identification information in a request received in the client session and serving the request on the primary server.

36. A system for replicating information in a client session, comprising:

a. a plurality of session servers;

b. a primary server in said plurality of session servers, said primary server adapted to receive a request in a client session and serve a response to that request, said primary server further adapted to store session information for that client session, and adapted to generate a cookie containing information relating to said primary server and transmit the cookie to the session client;

c. a secondary server in said plurality of session servers selected by said primary server, said secondary server adapted to receive the session information from said primary server and store the session information, the secondary server further receiving a request in a client session and serve a response to that request; and

d. a web server containing load-balancing logic for selecting said primary server, said web server adapted to receive an initial request from a client and direct that request to said primary server, said web server further adapted to receive a subsequent request from a client, the subsequent request containing identification information for said primary and secondary servers, the web server adapted to process the identification information and serve the process request on said primary server, the web server further adapted to serve the request on said secondary server if said primary server is unable to process the request wherein the client session information is sufficient for the secondary server to maintain the client session;

wherein the session information allows the primary or secondary server to provide client specific responses to client requests, the session information allowing the primary or secondary server to continue a previously started internet session by serving the response to the request using client session data from the session information.

37. A method for providing redundancy in a client session, comprising:

a. making a load balancing decision for an initial request from a client in a client session in order to select a primary server from a plurality of session servers;

b. serving said request on said primary server;

c. sending session information for that client session from the primary server to a secondary server selected by said primary server;

d. storing a cookie on the session client, the cookie containing information identifying the primary and secondary servers;

e. reading the identification information received with any subsequent request in the client session and serving that subsequent request on the primary server; and

f. updating session information on the primary and secondary servers each time a subsequent request is served on the primary server for that client session wherein the client session information is sufficient for the secondary server to maintain the client session;

wherein the session information allows the primary or secondary server to provide client specific responses to client requests, the session information allowing the primary or secondary server to continue a previously started internet session by serving the response to the request using client session data from the session information.

38. A method for providing redundancy in a client session, comprising:

a. selecting a primary server from a plurality of session servers in response to an initial request from a client;

b. serving said request on said primary server to begin a client session;

c. selecting a secondary server;

d. sending session information for that client session from the primary server to the secondary server; and

e. updating session information on the primary and secondary servers each time a request is received in the client session wherein the client session information is sufficient for the secondary server to maintain the client session;

wherein the session information allows the primary or secondary server to provide client specific responses to client requests, the session information allowing the primary or secondary server to continue a previously started internet session by serving the response to the request using client session data from the session information.

39. A method according to claim 38, further comprising:

storing the information in a cookie on the client.

40. A method according to claim 38, further comprising:

serving the request on the secondary server if the primary server is unable to process the request.

41. A method according to claim 40, further comprising:

selecting a new secondary server.

42. A method according to claim 38, further comprising:

serving requests to the primary server in batches.

43. A method according to claim 38, further comprising:

sending session information for that client session from the primary server to the secondary server in batches.