Global server load balancing

• US 8,024,441 B2
• Filed: 02/16/2007
• Issued: 09/20/2011
• Est. Priority Date: 09/26/2000
• Status: Expired due to Fees

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Brocade Communications Systems, Inc. (Broadcom, Inc.)
• Inventors: Kommula, Sunanda Lakshmi, Hsu, Ivy Pei-Shan, Jalan, Rajkumar, Cheung, David Chun Ying
• Primary Examiner(s): EL CHANTI, HUSSEIN A
• Application Number:
  US11/707,697
• Publication Number:
  US 20100082787A1
• Time in Patent Office: 1,677 Days
• Field of Search: 709217-219, 709/223, 709/224
• US Class Current: 709/223
• 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 67/1012 based on compliance of requirements or conditions with available server resources
• CPC Class Codes: H04L 67/1021 based on client or server locations

Abstract

A global server load-balancing (GSLB) switch serves as a proxy to an authoritative DNS and communicates with numerous site switches that are coupled to host servers serving specific applications. The GSLB switch receives from site switches operational information regarding host servers within the site switches neighborhood. When a client program requests a resolution of a host name, the GSLB switch, acting as a proxy of an authoritative DNS, returns one or more ordered IP addresses for the host name. The IP addresses are ordered using metrics that include the information collected from the site switches. In one instance, the GSLB switch places the address that is deemed “best” at the top of the list.

Claims

1. An apparatus, comprising:

a load balance switch that includes;

switch hardware; and

a controller adapted to calculate an average load of new connections to each respective site switch of a plurality of site switches, and to rank virtual IP addresses of the site switches based on the calculated average load of new connections to each said site switch,

wherein a number of said new connections is determined at least in part using a weighted sampling interval of a plurality of sampling intervals,

wherein at least one sampling interval of the plurality of sampling intervals is configurable with a weight of one and at least another sampling interval of the plurality of sampling intervals is configurable with a non-zero weight other than one.

2. The apparatus of claim 1 wherein said number of said new connections is determined using a sampling rate and said weighted sampling interval.

3. The apparatus of claim 2 wherein said load balance switch is configurable with its own at least one virtual IP address, and said load balance switch further includes:

a metric agent to sample a number of new connections to the load balance switch for the at least one virtual IP address configured on the load balance switch, using a sampling rate and a sampling interval, and to provide information resulting from the sampling to the controller, wherein the controller is adapted to calculate an average load of new connections to the load balance switch based on the provided information resulting from the sampling, and

wherein the controller is adapted to perform said ranking of the virtual IP addresses based also on the calculated average load of new connections to the load balance switch.

4. The apparatus of claim 1 wherein the controller is adapted to rank the virtual IP addresses by accepting a virtual IP address of any of said site switches that has a calculated average load of new connections less than a connection load limit and by rejecting a virtual IP address of any of said site switches that has a calculated average load of new connections greater than the connection load limit.

5. The apparatus of claim 1 wherein said controller is adapted to rank said virtual IP addresses based on a plurality of performance metrics.

6. The apparatus of claim 1 wherein still another sampling interval of the plurality of sampling intervals is configurable with a weight of 0 to nullify a contribution of said still another sampling interval.

7. An apparatus, comprising:

a load balance switch that includes;

switch hardware; and

a controller adapted to rank respective virtual IP addresses of respective site switches based on a calculated average load of new connections to each of said site switches,

wherein a number of said new connections is determined at least in part using a sampling interval that is configurable with a weight and that is included amongst a plurality of sampling intervals,

wherein intervals of said plurality of sampling intervals are configurable with non-zero weights that are different from each other.

8. The apparatus of claim 7 wherein the average load of new connections is calculated by the respective site switch using a sampling rate and said sampling interval that is configurable with the weight.

9. The apparatus of claim 7 wherein the controller is adapted to calculate the average load of new connections for the respective site switch using said number of new connections, which is received from the respective site switch.

10. The apparatus of claim 7 wherein the controller is adapted to rank the virtual IP addresses by accepting a virtual IP address of any of said site switches that has a calculated average load of new connections less than a connection load limit and by rejecting a virtual IP address of any of said site switches that has a calculated average load of new connections greater than the connection load limit.

11. The apparatus of claim 7 wherein said controller is adapted to rank said virtual IP addresses based on a plurality of performance metrics.

12. The apparatus of claim 7 wherein at least another sampling interval of the plurality of sampling intervals is configurable with a weight of 0 to nullify a contribution of said still another sampling interval.

13. The apparatus of claim 7 wherein said at least two sampling intervals of said plurality of sampling intervals that are configurable with non-zero weights that are different from each other include:

a first sampling interval configurable with a weight of one; and

a second sampling interval configurable with a non-zero weight other than one.

14. An apparatus, comprising:

a load balance switch that includes;

switch hardware;

a DNS proxy module adapted to receive a list of virtual IP addresses; and

a controller coupled to the DNS proxy module and adapted to arrange the received list of virtual IP addresses based on a calculated average load of new connections to each of said virtual IP addresses,

wherein a number of said new connections is determined at least in part using a sampling interval that is configurable with a weight and that is included amongst a plurality of sampling intervals,

wherein at least two sampling intervals of said plurality of sampling intervals are configurable with non-zero weights that are different from each other.

15. The apparatus of claim 14 wherein the load balance switch is also is configured with its own at least one virtual IP address, and said load balance switch further includes:

a metric agent adapted to sample new connections to the load balance switch for the at least one virtual IP address using a sampling rate and a sampling interval so as to obtain a number of new connections to the at least one virtual IP address, and to provide the obtained number of new connections to the controller for calculation of an average load of new connections to the at least one virtual IP address.

16. The apparatus of claim 14 wherein the controller is adapted to receive the calculated average load of new connections from each respective site switch of a plurality of site switches.

17. The apparatus of claim 15 wherein the calculated average load of new connections is calculated from said number of new connections as sampled using a sampling rate and said sampling interval that is configurable with the weight.

18. The apparatus of claim 14 wherein said controller is adapted to arrange said virtual IP addresses based on a plurality of performance metrics.

19. The apparatus of claim 14 wherein still another sampling interval of the plurality of sampling intervals is configurable with a weight of 0 to nullify a contribution of said still another sampling interval.

20. The apparatus of claim 14 wherein said at least two sampling intervals of said plurality of sampling intervals that are configurable with non-zero weights that are different from each other include:

a first sampling interval configurable with a weight of one; and

a second sampling interval configurable with a non-zero weight other than one.

21. An apparatus, comprising:

a load balance switch to receive a list of virtual IP addresses and that includes;

switch hardware; and

controller means for ranking the virtual IP addresses in the received list based on a calculated average load of new connections to each of said virtual IP addresses,

wherein a number of said new connections is determined at least in part using a sampling interval that is configurable with a weight and that is included amongst a plurality of sampling intervals,

wherein at least two sampling intervals of said plurality of sampling intervals are configurable with non-zero weights that are different from each other.

22. The apparatus of claim 21, wherein:

at least one virtual IP address is configurable on the load balance switch; and

said controller means for ranking ranks said virtual IP addresses based on a plurality of performance metrics.

23. The apparatus of claim 21 wherein the calculated average load of new connections is received from each respective site switch of a plurality of site switches.

24. The apparatus of claim 21 wherein the controller means for ranking calculates the average load of new connections from said number of new connections as sampled using a sampling rate and said sampling interval that is configurable with the weight.

25. The apparatus of claim 21 wherein still another sampling interval of the plurality of sampling intervals is configurable with a weight of 0 to nullify a contribution of said still another sampling interval.

26. The apparatus of claim 21 wherein said at least two sampling intervals of said plurality of sampling intervals that are configurable with non-zero weights that are different from each other include:

a first sampling interval configurable with a weight of one; and

a second sampling interval configurable with a non-zero weight other than one.

27. A method, comprising:

receiving, by a load balance switch having switch hardware, a list of virtual IP addresses; and

ranking, by said load balance switch, the virtual IP addresses in the received list based on a calculated average load of new connections to each of said virtual IP addresses,

wherein a number of said new connections is determined at least in part using a sampling interval that is configurable with a weight and that is included amongst a plurality of sampling intervals,

wherein at least two sampling intervals of said plurality of sampling intervals are configurable with non-zero weights that are different from each other.

28. The method of claim 27 wherein:

at least one virtual IP address is configurable on the load balance switch; and

new connections to the at least one virtual IP address on the load balance switch is obtained using a sampling rate and a sampling interval.

29. The method of claim 27 wherein the calculated average load of new connections is received by said load balance switch from each respective site switch of a plurality of site switches.

30. The method of claim 27, further comprising calculating, by said load balance switch, the average load of new connections from said number of new connections as sampled using a sampling rate and said sampling interval that is configurable with the weight.

31. The method of claim 27 wherein said at least two sampling intervals of said plurality of sampling intervals that are configurable with non-zero weights that are different from each other include:

a first sampling interval configurable with a weight of one; and

a second sampling interval configurable with a non-zero weight other than one.

32. A system, comprising:

a plurality of site switches, each site switch being respectively configured with a virtual IP address; and

a load balance switch configured to balance load, amongst the plurality of site switches, according to a set of performance metrics so as to select a preferred virtual IP address configured at one of the site switches,

wherein the set of performance metrics includes a metric based on a calculated average load of new connections to each of the plurality of site switches,

wherein a number of said new connections is determined at least in part using a weighted sampling interval of a plurality of sampling intervals,

wherein at least one sampling interval of the plurality of sampling intervals is configurable with a weight of one and at least another sampling interval of the plurality of sampling intervals is configurable with a non-zero weight other than one.

33. The system of claim 32, further comprising an authoritative domain name server coupled to the load balance switch, wherein the load balance switch is further configured to be a proxy to said authoritative domain name server, and wherein the load balance switch is configured to said balance load by use of said set of performance metrics to arrange virtual IP addresses in a list received from the authoritative domain name server.