Dynamic reconfiguration of network servers

• US 6,240,454 B1
• Filed: 09/09/1996
• Issued: 05/29/2001
• Est. Priority Date: 09/09/1996
• Status: Expired due to Term

• Current Assignee: Avaya Incorporated
• Original Assignee: Avaya Technology Corporation Miami Lakes FLA US
• Inventors: Nepustil, Vladimir
• Primary Examiner(s): Donaghue, Larry D.
• Application Number:
  US08/711,189
• Time in Patent Office: 1,723 Days
• Field of Search: 395/675, 709/105, 709/104, 709/239, 709/228, 709/229, 709/203
• US Class Current: 709/229
• CPC Class Codes: G06F 9/5083 Techniques for rebalancing the load in a distributed system

Abstract

One or more portions (221) of a database (220) which a primary server (106) uses to process client requests are duplicated (211) on one or more supplemental servers (105). As the clients demand for service increases and the processing load on the primary server becomes excessive (400), the primary server automatically off-loads the processing of those portions of the client requests that require one or more of the duplicated portions onto the supplemental servers by substituting (402) a secondary page (253) or a secondary object in its database that points to the one or more duplicated portions in the supplemental servers for a corresponding primary page (252) or a primary object in its database that points to the one or more duplicated portions in its database. The supplemental servers then serve the portions of the client requests that require the one or more of the duplicated portions. As demand for service decreases and the primary server becomes underloaded (404), it automatically restores (406) the primary page or the primary object in its database and resumes serving the entire client requests.

Claims

1. A client-server system comprising:

a plurality of servers for processing client requests;

at least one first server of the plurality of servers having first information and further having second information related to the first information, for processing client requests for the first information by sending to the clients the first information along with a first link to the second information that causes client requests for the second information to be directed to the at least one first server and further processing client requests directed to the at least one first server for the second information by sending to the clients the second information of the at least one first server, while a processing load on the at least one server is not excessive, and for processing the client requests for the first information by sending to the clients the first information along with a second link to the second information that causes the client requests for the second information to be redirected to the at least one second server for processing, in response to the processing load on the at least one first server becoming excessive; and

the at least one second server of the plurality of servers also having the second information, for processing the client requests redirected to the at least one second server for the second information by sending to the clients the second information of the at least one second server, automatically in response to the redirection.

2. The system of claim 1 wherein:

the at least one second server has the second information but does not have the first information, for processing the redirected client requests for the second information but not for processing the client requests for the first information.

3. The system of claim 1 wherein:

the first information includes a primary page or object including the first link that points to the second information of the at least one first server while the processing load on the at least one first server is not excessive, and includes a secondary page or object including the second link that points to the second information of the at least one second server in response to the processing load on the at least one first server becoming excessive.

4. The system of claim 2 wherein:

the at least one first server processes both client requests while the processing load on the at least one first server does not exceed a predetermined limit, and processes the client requests for the first information without also processing the client requests for the second information and causes the client requests for the second information to be redirected to the at least one second server in response to the processing load on the at least one first server exceeding the predetermined limit.

5. The system of claim 4 wherein:

said predetermined limit is a first predetermined first limit, and the at least one first server automatically ceases redirecting the client requests for the second information and resumes processing of both client requests in response to the processing load on the at least one first server falling below a predetermined second limit.

6. The system of claim 1 wherein:

the at least one first server further has third information related to the first information, processes the client requests for the first information by sending to the clients the first information along with the first link and a third link to the third information that causes client requests for the third information to be directed to the at least one first server, processes the client requests for the second information by sending to the clients the second information of the first server, and processes client requests for the third information by sending to the clients the third information of the first server while the processing load on the at least one server does not exceed a predetermined first limit, processes the client requests for the first information by sending to the clients the first information along with the second link and the third link, and processes the client requests for the third information by sending to the clients the third information of the at least one first server in response to the processing load on the at least one first server exceeding the predetermined first limit for a first time, and processes the client requests for the first information by sending to the clients the first information along with the second link and a fourth link to the third information that causes the client requests for the third information be redirected to at least one third server of the plurality of servers for processing, in response to the processing load on the at least one first server exceeding the predetermined first limit for a second consecutive time;

the at least one third server of the plurality of servers also has the third information, for processing the client requests for the third information redirected to the at least one third server by sending to the clients the third information of the at least one third server upon the processing load on the at least one first server exceeding the predetermined first limit for the second consecutive time; and

the at least one first server further automatically ceases causing redirection and resumes processing of the client requests for one of the second and the third information in response to the processing load on the at least one first server falling below a predetermined second limit for a first time, and automatically ceases causing redirection and resumes processing of the client requests for another of the second and the third information in response to the processing load on the at least one first server falling below the predetermined second limit for a second consecutive time.

7. A method of operating a client-server system that comprises a plurality of servers for processing client requests, comprising the steps of:

processing client requests for first information by sending to the clients the first information along with a first link to second information that causes client requests for the second information to be directed to at least one first server, and processing client requests directed to the at least one first server for the second information related to the first information by sending to the clients the second information of the at least one server, in the at least one first server of the plurality of servers, which at least one first server has both the first information and the second information, while a processing load on the at least one first server is not excessive;

processing the client requests for the first information in the at least one first server by sending to the clients the first information along with a second link to the second information that causes the client requests for the second information to be redirected to at least one second server of the plurality of servers, which at least one second server also has the second information, in response to the processing load on the at least one first server becoming excessive; and

automatically processing the client requests redirected to the at least one second server for the second information in the at least one second server by sending to the clients the second information of the at least one second server, in response to the redirection.

8. The method of claim 7 further comprising the steps of:

automatically ceasing to redirect the client requests for the second information in response to the processing load on the at least one first server falling below a predetermined level; and

automatically resuming processing of both client requests in the at least one server, in response to the processing load on the at least one first server falling below the predetermined level.