Method and apparatus for reconfiguring a server system

• US 20050066014A1
• Filed: 06/27/2002
• Published: 03/24/2005
• Est. Priority Date: 02/13/2002
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Willehadson, Stefan, Danne, Anders, Blomme, Max
• Granted Patent: US 7,739,364 B2
• Time in Patent Office: Days
• US Class Current: 709/220
• CPC Class Codes: G06F 2209/5016 Session
• CPC Class Codes: G06F 9/505 considering the load

Abstract

A method and apparatus for dynamically reconfiguring a server system (200). When a new server configuration is applied, a previous server configuration is saved. When receiving service requests, a first server is selected by using a first scheduling algorithm according to the new configuration. If the selected server was incorrect, a second server is selected by using a second scheduling algorithm according to the saved previous configuration. User data associated with the received service request is moved from the second server, if correct, to the first server. In this way, stored data will be gradually and dynamically re-organised from the old configuration to the new configuration in a relatively simple way.

Claims

1. A method of dynamically reconfiguring a server system comprising a plurality of servers for handling incoming service requests, comprising the steps of:

A) applying a new server configuration,

B) saving a previous server configuration, wherein the following steps are executed when receiving service requests;

C) selecting a server for handling a received service request, by using a first scheduling algorithm according to the new configuration,

D) selecting a server by using a second scheduling algorithm according to the previous configuration saved in step B), if the server selected in step C) was incorrect, and

E) moving user data associated with the received service request from the server selected in step D), if correct, to the server selected in step C).

2. A method according to claim 1, comprising the further step of selecting a server by using a scheduling algorithm according to a saved even earlier configuration, if the server selected in step D) was also incorrect.

3. A method according to claim 1, wherein the scheduling algorithms are hashing algorithms.

4. A method according to claim 3, wherein using the hashing algorithms includes deriving a hash number from a user ID and calculating a server ID number from the derived a hash number.

5. A method according to claim 4, comprising using the following algorithm:

server ID=hash (user ID)modulo n  

 

(1)

where n is the number of possible servers, and the modulo operator providing an integer between 0 and n-1.

6. A method according to claim 5, wherein the new configuration involves a changed number of servers, and that in the second scheduling algorithm, n is changed accordingly from the first scheduling algorithm.

7. A method according to claim 1, wherein the service requests involve storing tasks.

8. A method according to claim 7, wherein the storing tasks include any of:

storing new data, updating already stored data, and retrieving stored data.

9. A method according to claim 1, wherein step A) of applying a new server configuration includes storing new configuration data in a central administrator or the like, which can be accessed by the servers.

10. A method according to claim 9, wherein new configuration data is pushed from the central administrator to one or more servers.

11. A method according to claim 9, wherein new configuration data is retrieved from the central administrator by sending a request from a server.

21. A computer program comprising a software code being adapted to perform the method of claim 1 in a server system.

12. An apparatus for reconfiguring a server system, the server system comprising a plurality of servers being capable of performing at least one common storing task, and a scheduling unit configured to select servers for handling incoming service requests, the apparatus further comprising:

means for applying a new server configuration,

means for saving a previous server configuration,

means for selecting a first server for handling a received service request, by using a first scheduling algorithm according to the new configuration, and

means for selecting a second server by using a second scheduling algorithm according to the previous configuration, if the first server was incorrect, and

means for moving user data associated with the received service request from the second server, if correct, to the first server.

13. An apparatus according to claim 12, further comprising;

means for selecting a server by using a scheduling algorithm according to an even earlier configuration, if the second server was also incorrect.

14. An apparatus according to claim 12, further comprising means for using hashing algorithms as scheduling algorithms.

15. An apparatus according to claim 14, further comprising means for deriving a hash number from a user ID and calculating a server ID number from the derived a hash number.

16. An apparatus according to claim 15, further comprising means for using the following algorithm:

server ID=hash (user ID)modulo n  

 

(1)

where n is the number of possible servers, and the modulo operator providing an integer between 0 and n-1.

17. An apparatus according to claim 12, further comprising a central administrator or the like for storing new configuration data, which can be accessed by the servers.

18. An apparatus according to claim 17, further comprising a local administrator or the like in each server for receiving new configuration data from the central administrator.

19. An apparatus according to claim 17, wherein the central administrator comprises means for pushing new configuration data to one or more servers.

20. An apparatus according to claim 18, wherein the local administrator comprises means for sending a request for new configuration data to the central administrator.