Method and system for performance balancing in a distributed computer system

• US 20060236324A1
• Filed: 04/14/2005
• Published: 10/19/2006
• Est. Priority Date: 04/14/2005
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Tantawi, Asser N., Gissel, Thomas R.
• Granted Patent: US 7,725,901 B2
• Time in Patent Office: Days
• US Class Current: 718/105
• CPC Class Codes: G06F 2209/508 Monitor
• CPC Class Codes: G06F 9/5083 Techniques for rebalancing the load in a distributed system

Abstract

A method of dynamic performance balancing in a distributed computer system including collecting average service time statistics for application requests distributed from multiple application servers and collecting application server CPU utilization statistics from multiple hosts where each host is associated with at least one of the application servers. In addition, the method includes periodically calculating scaled routing weights from the average service time and CPU utilization statistics and distributing server requests to the application servers in accordance with the scaled routing weights. Also disclosed is a distributed computer system configured to accomplish dynamic performance balancing as described above, and an article of manufacture for use in programming a distributed computer system containing instructions to accomplish dynamic performance balancing of server requests as described above.

Claims

1. A method of dynamic performance balancing in a distributed computer system comprising:

collecting an average service time statistic from multiple application servers;

collecting a CPU utilization statistic from multiple hosts where each host is associated with at least one of the application servers;

periodically calculating scaled routing weights from the average service time statistics and the CPU utilization statistics; and

distributing server requests to the application servers in accordance with the scaled routing weights.

2. The method of dynamic performance balancing of claim 1 further comprising calculating a relative performance measure for each of the multiple application servers by comparing the average service time statistic for each of the multiple application servers to the average service time statistics collected for all of the multiple application servers.

3. The method of dynamic performance balancing of claim 2 further comprising calculating an error function for each of the multiple application servers by determining the deviation of the relative performance measure for each of the multiple application servers from the relative performance measures collected for all of the multiple application servers.

4. The method of dynamic performance balancing of claim 3 further comprising applying PID control to the error functions and select proportional, integral and derivative gains to calculate base routing weights.

5. The method of dynamic performance balancing of claim 4 further comprising adjusting the base routing weights with the CPU utilization statistics to calculate scaled routing weights.

6. The method of dynamic performance balancing of claim 4 further comprising adjusting the base routing weights with a limiting factor to calculate scaled routing weights.

7. The method of dynamic performance balancing of claim 4 further comprising adjusting the base routing weights with a scaling factor to calculate scaled routing weights.

8. A distributed computing system comprising:

multiple hosts with each host being associated with one or more nodes and with each node being associated with one or more application servers and a monitoring agent;

a performance balancer configured to receive an average service time statistic calculated for each of the application servers and a CPU utilization statistic calculated for each of the hosts;

a weight calculator associated with the performance balancer configured to periodically calculate scaled routing weights from the average service time statistics and the CPU utilization statistics; and

a router configured to receive the scaled routing weights from the performance balancer and distribute server requests to the application servers in accordance with the scaled routing weights.

9. The distributed computing system of claim 8 further comprising means for calculating a relative performance measure and an error function for each of the multiple application servers by comparing the average service time statistic for each of the multiple application servers to the average service time statistics collected for all of the multiple application servers.

10. The distributed computing system of claim 9 further comprising means for applying PID control to the error functions and select proportional, integral and derivative gains to calculate base routing weights.

11. The distributed computing system of claim 10 further comprising means for adjusting the base routing weights with the CPU utilization statistics to calculate scaled routing weights.

12. The distributed computing system of claim 10 further comprising means for adjusting the base routing weights with a limiting factor to calculate scaled routing weights.

13. The distributed computing system of claim 10 further comprising means for adjusting the base routing weights with a scaling factor to calculate scaled routing weights.

14. An article of manufacture for use in programming a data storage system to perform dynamic performance balancing in a distributed computer system the article of manufacture comprising instructions for:

collecting an average service time statistic from multiple application servers;

collecting a CPU utilization statistic from multiple hosts where each host is associated with at least one of the application servers;

periodically calculating scaled routing weights from the average service time statistics and the CPU utilization statistics; and

distributing server requests to the application servers in accordance with the scaled routing weights.

15. The article of manufacture of claim 14 further comprising instructions for calculating a relative performance measure for each of the multiple application servers by comparing the average service time statistic for each of the multiple application servers to the average service time statistics collected for all of the multiple application servers.

16. The article of manufacture of claim 15 further comprising instructions for calculating an error function for each of the multiple application servers by determining the deviation of the relative performance measure for each of the multiple application servers from the relative performance measures collected for all of the multiple application servers.

17. The article of manufacture of claim 16 further comprising instructions for applying PID control to the error functions and select proportional, integral and derivative gains to calculate base routing weights.

18. The article of manufacture of claim 17 further comprising instructions for adjusting the base routing weights with the CPU utilization statistics to calculate scaled routing weights.

19. The article of manufacture of claim 17 further comprising instructions for adjusting the base routing weights with a limiting factor to calculate scaled routing weights.

20. The article of manufacture of claim 17 further comprising instructions for adjusting the base routing weights with a scaling factor to calculate scaled routing weights.