Load balancing content requests using dynamic document generation cost information

• US 20020178259A1
• Filed: 05/23/2001
• Published: 11/28/2002
• Est. Priority Date: 05/23/2001
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Doyle, Ronald P., Hind, John R.
• Granted Patent: US 6,839,700 B2
• Time in Patent Office: Days
• US Class Current: 709/225
• 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 67/101 based on network conditions
• CPC Class Codes: H04L 67/1012 based on compliance of requirements or conditions with available server resources
• CPC Class Codes: H04L 67/1029 using data related to the state of servers by a load balancer
• 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 9/40 Network security protocols
• CPC Class Codes: Y10S 707/99932 Access augmentation or optimizing

Abstract

Methods, systems, computer program products, and methods of doing business by performing load balancing of content requests using information regarding the cost of dynamically creating the requested document content. Cost metrics are gathered by a server which generates requested content, and may reflect processing at one or more other servers. This cost information is provided to a load balancing host. Several alternative approaches for providing the cost metrics may be used, including defining new headers for response messages, specifying cookie values, and so forth. The load balancing host may choose to route a subsequent request for that content to the server which most recently generated the content, or to another available server, depending on the cost of re-generating the content and the current load on those servers.

Claims

1. A method of improving load balancing operations in a computing network using cost metrics, comprising steps of:

obtaining cost metrics representing a cost of generating document content;

receiving a request for particular document content; and

using the obtained cost metrics as a factor when routing the request to a selected one of a plurality of servers.

2. The method according to claim 1, further comprising the step of determining a particular one of the plurality servers which most recently served the requested document content, and wherein the using step further comprises steps of:

determining which one of the plurality of servers is (1) capable of serving the requested document content and (2) most lightly loaded;

comparing a first cost of routing the request to the determined one to a second cost of routing the request to the particular one; and

selecting the determined one if the first cost is less than the second cost and selecting the particular one otherwise.

3. The method according to claim 2, wherein the first cost and the second cost include a current load on the determined one and the particular one, respectively.

4. The method according to claim 1, wherein:

the obtaining step further comprises the step of receiving meta-data which conveys the cost metrics for the document content; and

the using step further comprises the step of using the cost metrics from the received meta-data.

5. The method according to claim 4, wherein the received meta-data comprises one or more cookies.

6. The method according to claim 4, wherein the received meta-data comprises a HyperText Transfer Protocol (“

HTTP”

) response header.

7. The method according to claim 4, wherein the received meta-data comprises a plurality HyperText Transfer Protocol (“

HTTP”

) response headers, each of the headers conveying an element of the cost metric for a particular document content.

8. The method according to claim 4, wherein the received meta-data comprises syntax in a markup language.

9. The method according to claim 8, wherein the markup language is HTML (“

HyperText Markup Language”

).

10. The method according to claim 9, wherein the syntax comprises a “

META”

tag using an “

HTTP-EQUIV”

attribute syntax.

11. The method according to claim 9, wherein the syntax comprises a “

META”

tag using a “

NAME”

attribute syntax.

12. The method according to claim 9, wherein the syntax comprises a specially-denoted comment.

13. The method according to claim 8, wherein the markup language is XML (“

Extensible Markup Language”

).

14. The method according to claim 1, wherein the obtaining step further comprises querying remotely-stored cost metric information.

15. The method according to claim 14, wherein the querying step uses a WebDAV request.

16. The method according to claim 15, wherein a response to the WebDAV request specifies cost metrics for more than one of the plurality of servers.

17. The method according to claim 1, further comprising the steps of:

determining a particular one of the plurality servers which most recently served the requested document content;

determining a current workload on the particular one;

determining the other ones of the plurality of servers which are capable of serving the requested document content;

determining the current workload on each of the determined other ones; and

determining a lesser of the current workloads on each of the determined other ones; and

wherein the using step further comprises steps of;

comparing a first cost of routing the request to the determined one, given its determined current workload, to a second cost of routing the request to the server which has the determined lesser of the current workloads, given that lesser current workload; and

selecting the determined one if the first cost is less than the second cost and selecting the server which has the determined lesser of the current workloads otherwise.

18. A system for improving load balancing operations in a computing network using cost metrics, comprising:

means for obtaining cost metrics representing a cost of generating document content;

means for receiving a request for particular document content;

means for responding to the request using cached content, if available; and

means for using the obtained cost metrics as a factor when routing the request to a selected one of a plurality of servers, when cached content is not available.

19. A computer program product for improving load balancing operations in a computing network using cost metrics, the computer program product embodied on one or more computer-readable media and comprising:

computer-readable program code means for obtaining cost metrics representing a cost of generating document content;

computer-readable program code means for receiving a request for particular document content;

computer-readable program code means for responding to the request using cached content, if available; and

computer-readable program code means for using the obtained cost metrics as a factor when routing the request to a selected one of a plurality of servers, when cached content is not available

20. A method of using cost metrics when load balancing incoming content requests in a networking environment, comprising steps of:

gathering cost metric information representing a cost of generating document content; and

creating meta-data to convey the cost metric information to a load balancer.

21. The method according to claim 20, further comprising the step of sending the created meta-data to the load balancer.

22. The method according to claim 20, wherein the gathered cost metric information comprises at least one of:

(1) processing time at an origin server;

(2) network costs from the origin server to one or more backend enterprise servers;

(3) processing time at the backend enterprise servers; and

(4) a cost of delivering the generated document content to a proxy or cache.