FLEXIBLE HIGH AVILABILITY DISASTER RECOVERY WITH A SET OF DATABASE SERVERS

• US 20150301910A1
• Filed: 04/18/2014
• Published: 10/22/2015
• Est. Priority Date: 04/18/2014
• Status: Active Grant

• Current Assignee: Sybase Incorporated (SAP SE)
• Original Assignee: Jaikishan Dabhole
• Inventors: Fatemi, Taghi, Sathyanarayana, Ramanna, Dabhole, Jaikishan, Imbierski, Tony
• Granted Patent: US 9,400,720 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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: G06F 11/2048 where the redundant components share neither address space nor persistent storage
• CPC Class Codes: G06F 2201/80 Database-specific techniques

Abstract

Seamless failover in a database replication environment which has a primary database server and a plurality of standby database servers, is described. An example method includes orderly terminating transactions on the primary database server, where the transactions are originated from client applications. The transaction logs of the primary database server are drained and the transaction logs are replicated from the primary database server to the plurality of standby database servers. One of the standby database servers is designated as a new primary database server processing user transactions.

Claims

1. A method for seamless failover in a database replication environment comprising a primary database server and one or more standby database servers, the method comprising:

terminating transactions on the primary database server, wherein the transactions are originated from client applications;

draining transaction logs of the primary database server, wherein the transaction logs are replicated from the primary database server to the one or more standby database servers; and

designating one of the standby database servers as a new primary database server.

2. The method of claim 1, wherein the primary database server and the one or more standby database servers conduct asynchronous replication.

3. The method of claim 1, wherein the primary database server services transaction processing of the client applications.

4. The method of claim 1, further comprising:

receiving connection requests from the client applications to the standby database servers; and

redirecting the connection requests to the primary database server.

5. The method of claim 1, wherein the primary database server and the standby database servers reside on different platforms or platforms with different versions.

6. The method of claim 1, further comprising:

resuming transaction processing of the client applications by the new primary database server.

7. The method of claim 1, wherein the terminating comprises:

deactivating the primary database server via a deactivate command, with which the primary database server is put in an inactive state via a termination of transaction activities.

8. The method of claim 1, wherein the primary database server and the one or more standby database servers are geographically remote.

9. The method of claim 1, further comprising:

demoting the primary database server to a member of the one or more standby database servers; and

changing a direction of replication from the new primary database server to the one or more standby database servers including the standby database server which was demoted.

10. The method of claim 1, farther comprising:

performing failover from the primary database server to a companion database server, wherein the companion database server is geographically close to the primary database server and wherein the primary database server and the companion database server implement synchronous data replication.

11. A system for seamless failover in a database replication environment comprising a primary database server and one or more standby database servers, the system comprising:

a memory; and

at least one processor coupled to the memory and configured to execute a plurality of modules, the modules comprising;

a transaction terminator, configured to terminate transactions on the primary database server, wherein the transactions are originated from client applications,

a log drainer, configured to drain transaction logs of the primary database server, wherein the transaction logs are replicated from the primary database server to the one or more standby database servers, and

a server designator, configured to designate one of the standby database servers as a new primary database server.

12. The system of claim 11, wherein the primary database server and the one or more standby database servers conduct asynchronous replication.

13. The system of claim 11, wherein the primary database server services transaction processing of the client applications.

14. The system of claim 11, further comprising:

a connection receiver, configured to receive connection requests from the client applications to the standby database servers, and

a connection redirector, configured to redirect the connection requests to the primary database server.

15. The system of claim 11, wherein the log drainer is configured to:

apply changes captured in the transaction logs of the primary database server to the standby database servers.

16. The system of claim 11, further comprising:

a transaction resumer, configured to resume transaction processing of the client applications by the new primary database server.

17. The system of claim 11, wherein the transaction terminator is configured to:

deactivate the primary database server via a deactivate command, which the primary database server is put in an inactive state via a termination of transaction activities.

18. The system of claim 11, wherein the primary database server and the one or more standby database servers are geographically remote.

19. The system of claim 11, further comprising:

a server demoter, configured to demote the primary database server to a member of the one or more standby database servers; and

a replication reverser, configured to change a direction of replication from the new primary database server to the one or more standby database servers including the standby database which was demoted.

20. A tangible computer readable storage medium having instructions encoded thereon, execution of which, by a processor, cause the processor to perform operations for seamless failover in a database replication environment comprising a primary database server and one or more database servers, the operations comprising:

terminating transactions on the primary database server, wherein the transactions are originated from client applications;

draining transaction logs of the primary database server, wherein the transaction logs are replicated from the primary database server to the one or more standby database servers; and

designating one of the standby database servers as a new primary database server.