Load balancing apparatus and method

• US 20050267970A1
• Filed: 09/20/2004
• Published: 12/01/2005
• Est. Priority Date: 05/11/2004
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Sugizaki, Atsuya
• Granted Patent: US 7,437,461 B2
• Time in Patent Office: Days
• US Class Current: 709/225
• CPC Class Codes: H04L 67/04 specially adapted for terminals or networks with limited capabilities; specially adapted for terminal portability
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• 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 67/1034 Reaction to server failures by a load balancer
• CPC Class Codes: H04L 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• CPC Class Codes: H04L 67/63 Routing a service request depending on the request content or context
• CPC Class Codes: H04L 69/40 for recovering from a failure of a protocol instance or entity, e.g. service redundancy protocols, protocol state redundancy or protocol service redirection management of faults, events, alarms or notifications in data switching networks H04L41/06

Abstract

An object of this invention is to suppress influence due to a server trouble. This load balancing method comprises: if it is detected that a trouble occurred in a first server included in plural servers, selecting a second server other than the first server from the plural servers as a new transfer destination of a processing request from a user terminal whose transfer destination of the processing request is set to the first server; and generating and storing into a connection management data storage, setting data to transfer the processing request from the user terminal whose transfer destination of the processing request is set to the first server to the second server via a transfer route determined based on a predetermined rule. Thus, the processing request from the user terminal associated with the first server in which the trouble occurred is transferred to another normal second server, appropriately.

Claims

1. A load balancing apparatus for transferring a processing request from a user terminal to either of a plurality of servers, comprising:

a selector that selects, if it is detected that a trouble occurred in a first server included in said plurality of servers, a second server other than said first server from said plurality of servers as a new transfer destination of said processing request from a user terminal whose transfer destination of said processing request is set to said first server; and

a generator that generates and stores into a connection management data storage, setting data to transfer said processing request from said user terminal whose transfer destination of said processing request is set to said first server to said second server via a transfer route determined based on a predetermined rule.

2. The load balancing apparatus as set forth in claim 1, wherein said transfer route is a new connection to said second server.

3. The load balancing apparatus as set forth in claim 1, wherein said transfer route is a connection to said second server, which is already established and being used.

4. The load balancing apparatus as set forth in claim 1, wherein said transfer route is a connection to said second server, which is already established and is not used.

5. The load balancing apparatus as set forth in claim 1, further comprising:

a unit that judges load states of said plurality of servers, and

wherein said predetermined rule is a rule to determine as said transfer route, a connection to said second server, which is already established and being used, in a case where it is judged that a load of said second server is higher than a predetermined reference, and to determine as said transfer route, a connection to said second server, which is already established and is not used, in a case where it is judged that said load of said second server is equal to or lower than said predetermined reference.

6. The load balancing apparatus as set forth in claim 1, further comprising:

a unit that judges load states of said plurality of servers, and

wherein said predetermined rule is a rule to determine as said transfer route, a connection to said second server, which is already established and being used, in a case where it is judged that a load of said second server is higher than a predetermined reference, and to determine as said transfer route, a new connection to said second server in a case where it is judged that said load of said second server is equal to or lower than said predetermined reference.

7. The load balancing apparatus as set forth in claim 1, wherein said predetermined rule is a rule to determine as said transfer route, a connection to said second server, which is already established and is not used, in a case where it is judged that said connection to said second server exists, and to determine as said transfer route, a new connection to said second server in a case where it is judged that only a connection being used in connections to said second server, which is already established.

8. The load balancing apparatus as set forth in claim 1, further comprising:

a unit that judges load states of said plurality of servers, and

wherein said predetermined rule is a rule to determine as said transfer route, a first connection to said second server, which is already established and being used, in a case where it is judged that a load of said second server is higher than a predetermined reference, to determine as said transfer route, a second connection to said second server, which is already established and is not used, in a case where it is judged that said load of said second server is equal to or lower than said predetermined reference and said second connection exists, and to determine as said transfer route, a new connection to said second server, in a case where it is judged that said load of said second server is equal to or lower than said predetermined reference and there are only connections being used in connections to said second server, which are already established.

9. The load balancing apparatus as set forth in claim 1, wherein said setting data includes data representing an address and a communication port of a transfer destination server.

10. The load balancing apparatus as set forth in claim 1, wherein said connection management data storage stores data representing an association between an address and a communication port of a user terminal as a processing request source and an address and a communication port of a server as a transfer destination, and

said load balancing apparatus further comprising:

a transfer unit that transfers a processing request from a user terminal to either of said plurality of servers based on data stored in said connection management data storage, and

wherein said transfer unit transfers a processing request before detecting that said trouble occurred in said first server among a series of processing requests from a specific user terminal, to said first server, and transfers a processing request after detecting that said trouble occurred in said first server among said series of said processing requests from said specific user terminal, to said second server.

11. A load balancing program embodied on a medium, for causing a processor to transfer a processing request from a user terminal to either of a plurality of servers, said load balancing program comprising:

if it is detected that a trouble occurred in a first server included in said plurality of servers, selecting a second server other than said first server from said plurality of servers as a new transfer destination of said processing request from a user terminal whose transfer destination of said processing request is set to said first server; and

generating and storing into a connection management data storage, setting data to transfer said processing request from said user terminal whose transfer destination of said processing request is set to said first server to said second server via a transfer route determined based on a predetermined rule.

12. The load balancing program as set forth in claim 11, wherein said transfer route is a new connection to said second server.

13. The load balancing program as set forth in claim 11, wherein said transfer route is a connection to said second server, which is already established and being used.

14. The load balancing program as set forth in claim 11, wherein said transfer route is a connection to said second server, which is already established and is not used.

15. The load balancing program as set forth in claim 11, further comprising:

judging load states of said plurality of servers, and

wherein said predetermined rule is a rule to determine as said transfer route, a first connection to said second server, which is already established and being used, in a case where it is judged that a load of said second server is higher than a predetermined reference, to determine as said transfer route, a second connection to said second server, which is already established and is not used, in a case where it is judged that said load of said second server is equal to or lower than said predetermined reference and said second connection exists, and to determine as said transfer route, a new connection to said second server, in a case where it is judged that said load of said second server is equal to or lower than said predetermined reference and there are only connections being used in connections to said second server, which are already established.

16. A load balancing method for transferring a processing request from a user terminal to either of a plurality of servers, said load balancing method comprising:

if it is detected that a trouble occurred in a first server included in said plurality of servers, selecting a second server other than said first server from said plurality of servers as a new transfer destination of said processing request from a user terminal whose transfer destination of said processing request is set to said first server; and

generating and storing into a connection management data storage, setting data to transfer said processing request from said user terminal whose transfer destination of said processing request is set to said first server to said second server via a transfer route determined based on a predetermined rule.