Method and system to clear counters used for statistical tracking for global server load balancing

• US 7,676,576 B1
• Filed: 02/28/2003
• Issued: 03/09/2010
• Est. Priority Date: 08/01/2002
• Status: Expired due to Fees

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Foundry Networks Incorporated (Broadcom, Inc.)
• Inventors: Kommula, Sunanda L.
• Primary Examiner(s): Flynn; Nathan
• Assistant Examiner(s): Joo; Joshua
• Application Number:
  US10/377,364
• Time in Patent Office: 2,566 Days
• Field of Search: 709223-226, 370229-230, 718/105
• US Class Current: 709/226
• CPC Class Codes: G06F 1/3209 Monitoring remote activity, e.g. over telephone lines or network connections
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies
• CPC Class Codes: H04L 43/0817 by checking functioning
• CPC Class Codes: H04L 43/0864 Round trip delays
• CPC Class Codes: H04L 43/16 Threshold monitoring
• CPC Class Codes: H04L 61/35 involving non-standard use of addresses for implementing network functionalities, e.g. coding subscription information within the address or functional addressing, i.e. assigning an address to a function
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• 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 67/101 based on network conditions
• CPC Class Codes: H04L 67/1014 based on the content of a request
• CPC Class Codes: H04L 67/1017 based on a round robin mechanism
• CPC Class Codes: H04L 67/1021 based on client or server locations
• CPC Class Codes: H04L 67/1023 based on a hash applied to IP addresses or costs

Abstract

Server load-balancing operation-related data, such as data associated with a system configured for global server load balancing (GSLB) that orders IP addresses into a list based on a set of performance metrics, is tracked. Such operation-related data includes inbound source IP addresses (e.g., the address of the originator of a DNS request), the requested host and zone, identification of the selected “best” IP addresses resulting from application of a GSLB algorithm, and the selection metric used to decide on an IP address as the “best” one. The data includes a count of the selected “best” IP addresses selected via application of the GSLB algorithm, and for each of these IP addresses, the list of deciding performance metrics, along with a count of the number of times each of these metrics in the list was used as a deciding factor in selection of this IP address as the best one. This tracking feature allows better understanding of GSLB policy decisions (such as those associated with performance, maintenance, and troubleshooting) and intelligent deployment of large-scale resilient GSLB networks. The counters can be cleared as needed and without having to reload the system.

Claims

1. A method for a load balance switch, the method comprising:

determining if at least one counter of a plurality of counters in the load balance switch has data indicative of selection by said load balance switch of a preferred address among a plurality of addresses, said plurality of addresses respectively corresponding to said plurality of counters; and

if it is determined that the at least one counter has the data, clearing all of said plurality of counters while maintaining existing communications to said plurality of addresses,

wherein said preferred address is selected based on a set of performance metrics, and wherein said data in said at least one counter includes respective counts of how many times each performance metric from said set of performance metrics was used as a deciding factor in selecting said preferred address.

2. The method of claim 1, further comprising determining if at least one address of said plurality of addresses has been previously inaccessible, and wherein said clearing is performed to have said at least one address considered equally by a load balancing algorithm of said load balance switch with respect to other addresses in said plurality of addresses.

3. The method of claim 2 wherein said clearing, performed to have said at least one address considered equally by the load balancing algorithm with respect to other addresses in said plurality of addresses, prevents said at least one address from being flooded with traffic when said at least one address comes back online from being inaccessible.

4. The method of claim 1, further comprising determining if a start of the load balance switch is to be performed.

5. The method of claim 1, further comprising determining if a test of the load balance switch is to be performed.

6. The method of claim 1 wherein said clearing all of said plurality of counters includes setting a count of each of said plurality of counters to zero.

7. The method of claim 1 wherein said clearing all of said plurality of counters includes clearing said plurality of counters globally for all zones.

8. The method of claim 1 wherein said clearing all of said plurality of counters includes clearing said plurality of counters corresponding to addresses in only a selected individual zone that is configured to be load balanced by said load balance switch and not clearing globally for all zones that are configured to be load balanced by said load balance switch.

9. The method of claim 1 wherein said clearing all of said plurality of counters includes clearing at least one of said counters in response to a software command.

10. The method of claim 1 wherein the data indicative of selection of the preferred address is used by said load balance switch in connection with at least one metric usable to identify the preferred address.

11. The method of claim 1 wherein said addresses, among which said load balance switch selects said preferred address, include virtual IP addresses respectively configured at a plurality of site switches remote from said load balance switch, and wherein at least one host server is respectively bound to each of said virtual IP addresses.

12. An article of manufacture, comprising:

a storage medium having instructions stored thereon that are executable by a load balance switch to;

determine if at least one counter in the load balance switch has data, said at least one counter corresponding to an address; and

clear the at least one counter, if the at least one counter is determined to have the data, such that existing communication to said address is maintained,

wherein said data in said at least one counter includes respective counts of how many times each performance metric from a set of performance metrics was used as a deciding factor in selecting a preferred address.

13. The article of manufacture of claim 12 wherein the instructions to clear the at least one counter include instructions to clear a plurality of counters globally for all zones.

14. The article of manufacture of claim 12 wherein the instructions to clear the at least one counter include instructions to clear a plurality of counters for only a selected individual zone that is configured to be load balanced by said load balance switch and not clear globally for all zones that are configured to be load balanced by said load balance switch.

15. The article of manufacture of claim 12 wherein the instructions to clear the at least one counter include instructions to set a count of said at least one counter to zero.

16. The article of manufacture of claim 12 wherein said address is included amongst a plurality of addresses, said plurality of addresses respectively corresponding to a plurality of said at least one counter, and wherein the instructions to clear said at least one counter include instructions executable by said load balance switch to:

clear all of said plurality of counters while maintaining existing communications to said plurality of addresses.

17. The article of manufacture of claim 16 wherein the storage medium further includes instructions stored thereon that are executable by said load balance switch to:

determine if at least one address of said plurality of addresses has been previously inaccessible and if a particular counter corresponding to said at least one address indicates a low selection count,

wherein the instructions to clear all of said plurality of counters includes instructions to reset all of said plurality of counters to zero, including said corresponding particular counter, so as to have said at least one address considered equally by a load balancing algorithm of said load balance switch with respect to other addresses in said plurality of addresses, when said at least one address comes back online.

18. The article of manufacture of claim 17 wherein said instructions to reset all of said plurality of counters to zero, so as to have said at least one address considered equally by the load balancing algorithm with respect to other addresses in said plurality of addresses, prevents said at least one address from being flooded with traffic when said at least one address comes back online from being inaccessible.

19. A load balance switch, comprising:

at least one hardware counter corresponding to an address; and

a means for determining if said at least one counter has data, and for clearing the at least one counter, if the at least one counter is determined to have the data, such that existing communication to said address is maintained,

wherein said data in said at least one counter includes respective counts of how many times each performance metric from a set of performance metrics was used as a deciding factor in selecting a preferred address.

20. The load balance switch of claim 19 wherein the means for clearing the at least one counter clears a plurality of counters globally for all zones.

21. The load balance switch of claim 19 wherein the means for clearing the at least one counter clears a plurality counters for only a selected individual zone that is configured to be load balanced by said load balance switch and does not clear globally for all zones that are configured to be load balanced by said load balance switch.

22. The load balance switch of claim 19 wherein said address is included amongst a plurality of addresses, said plurality of addresses respectively corresponding to a plurality of counters, and wherein said means for clearing clears all of said plurality of counters, if said at least one counter is determined to have the data, such that existing communications to said plurality of addresses is maintained.

23. A load balance switch, comprising:

at least one data repository to store count data corresponding to an address;

a controller coupled to the data repository to control storage of the data in the at least one data repository; and

a component responsive to the controller to clear the at least one data repository of said stored count data such that existing communication to said address is maintained,

wherein said data stored in said at least one data repository includes respective counts of how many times each performance metric from a set of performance metrics was used as a deciding factor in selecting a referred address.

24. The load balance switch of claim 23 wherein the at least one data repository comprises a counter to count each time an address is selected as a preferred address.

25. The load balance switch of claim 24 wherein the at least one data repository further includes software.

26. The load balance switch of claim 23 wherein the component to clear the at least one data repository uses a software command.

27. The load balance switch of claim 23 wherein the component to clear the at least one data repository globally clears all said count data corresponding to all zones.

28. The load balance switch of claim 23 wherein the component to clear the at least one data repository clears all said count data corresponding to only a selected one of a plurality of zones that is configured to be load balanced by said load balance switch and not clear globally for all zones that are configured to be load balanced by said load balance switch.

29. The load balance switch of claim 23 wherein the component to clear the at least one data repository clears all said count data corresponding to a plurality of addresses if at least one address of the plurality of addresses was previously inaccessible, so that said at least one address is considered equally by said controller with respect to other addresses in said plurality.

30. The load balance switch of claim 24 wherein clearance of the at least one data repository, by said component to have said at least one address considered equally by said controller with respect to other addresses in said plurality, prevents said at least one address from being flooded with traffic when said at least one address comes back online from being inaccessible.

31. The load balance switch of claim 23 wherein the component to clear the at least one data repository clears all said count data in the at least one data repository if at least one of a load balance start, a metric reorder, and a metric test is to be performed by the controller.

32. The load balance switch of claim 23 wherein said address is included amongst a plurality of addresses, said plurality of addresses respectively corresponding to a plurality of said at least one data repository, and wherein said component is adapted to clear all of said plurality of data repositories such that existing communications to said plurality of addresses is maintained.