Systems and methods for efficiently load balancing based on least connections

• US 8,077,622 B2
• Filed: 08/03/2007
• Issued: 12/13/2011
• Est. Priority Date: 08/03/2007
• Status: Active Grant

• Current Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Original Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Inventors: Kondamuru, Ravi, Bots, Henk, Suganthi, Josephine, Shetty, Anil
• Primary Examiner(s): Vu, Huy
• Assistant Examiner(s): MIAN, OMER S
• Application Number:
  US11/833,777
• Publication Number:
  US 20090034417A1
• Time in Patent Office: 1,593 Days
• Field of Search: 455/453, 709/226, 370/235, 370/237, 370/252
• US Class Current: 370/237
• 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 67/1017 based on a round robin mechanism

Abstract

Systems and methods for load balancing services based on fewest connections by decreasing granularity of service selection as a number of fewest connections serviced by the services increases may include establishing, by an appliance, a set of identifiers corresponding to a number of connections serviced by a service, the set comprising a first plurality of identifiers each identifying a predetermined number of connections and a second plurality of identifiers each identifying a predetermined range of numbers of connections. The appliance assigns, to each service servicing connections, an identifier corresponding to the number of connections serviced by the service, at least one of the identifiers selected from the second plurality of identifiers. The appliance receives a request for a service, and forwards the request to a service assigned to the identifier corresponding to a fewest number of connections with at least one service assigned to the identifier.

Claims

1. A method for more efficiently load balancing services based on fewest connections by decreasing granularity of service selection as a number of fewest connections serviced by the services increases, the method comprising:

(a) establishing, by a load balancing appliance intermediary to a plurality of clients and a plurality of servers, a table indexed by a set of identifiers corresponding to numbers of connections serviced by a service, the set of identifiers comprising a first plurality of identifiers each identifying a predetermined number of connections and a second plurality of identifiers each identifying a predetermined range of numbers of connections;

(b) assigning, by the load balancing appliance, an indicia of each of a plurality of services servicing connections to an entry in the table, an identifier indexing the entry corresponding to the number of connections serviced by the service, at least one of the identifiers selected from the second plurality of identifiers;

(c) receiving, by the appliance, a request for a service;

(d) determining, by the appliance, the identifier of the table corresponding to a fewest number of connections with an indicia of at least one service assigned to the identifier; and

(e) forwarding, by the appliance, the request to a service identified by the determined identifier.

2. The method of claim 1, wherein the identifiers correspond to a number of active connections serviced.

3. The method of claim 1, wherein each of the second plurality of identifiers identify a predetermined range of numbers of connections above a predetermined threshold.

4. The method of claim 1, wherein the second plurality of identifiers each identify a predetermined range of numbers of connections, and at least one range starting at a first number of connections comprises a larger range than at least one range starting at a second, lower, number of connections.

5. The method of claim 4, wherein the at least one range starting at a first number of connections comprises a smaller range than at least one range starting at a second, higher, number of connections.

6. The method of claim 1, wherein step (b) comprises assigning an indicia of a first service servicing a first number of connections to an entry in the table indexed by a first identifier selected from the second plurality of identifiers and assigning an indicia of a second service servicing a second number of connections to the entry in the table indexed by the first identifier, wherein the first number is different than the second number.

7. The method of claim 1, wherein step (e) comprises forwarding, by the appliance, the request to a service least recently forwarded a request, the service selected from a set of services whose indicia are stored in an entry in the table indexed by the determined identifier.

8. The method of claim 1, further comprising forwarding requests to a plurality of services whose indicia are stored in the same entry in the table in a round-robin manner.

9. The method of claim 1, further comprising determining an updated number of active connections serviced by the service;

and assigning an indicia of the service to an entry in the table based on the updated total number.

10. The method of claim 1, further comprising determining an updated number of active connections serviced by a second service;

and assigning an indicia of the second service to an entry in the table based on the number of active connections.

11. A load balancing appliance, intermediary to a plurality of clients and a plurality of servers, for more efficiently load balancing services based on fewest connections by decreasing granularity of service selection as a number of fewest connections serviced by the services increases, the appliance comprising:

a memory element which stores a table indexed by a set of identifiers corresponding to numbers of connections serviced by a service, the set of identifiers comprising a first plurality of identifiers each identifying a predetermined number of connections and a second plurality of identifiers each identifying a predetermined range of numbers of connections;

a receiver which receives a request for a service;

a processor in communication with the receiver and the storage element which assigns an indicia of each of a plurality of services servicing connections to an entry in the table, an identifier indexing the entry corresponding to the number of connections serviced by the service, at least one of the identifiers selected from the second plurality of identifiers; and

determines an identifier of the table corresponding to the fewest number of connections with an indicia of at least one service assigned to it; and

a transmitter, in communication with the processor which forwards the request to a service identified by the determined identifier.

12. The system of claim 11, wherein the identifiers correspond to a number of active connections serviced.

13. The system of claim 11, wherein each of the second plurality of identifiers identify a predetermined range of numbers of connections above a predetermined threshold.

14. The system of claim 11, wherein the second plurality of identifiers each identify a predetermined range of numbers of connections, and at least one range starting at a first number of connections comprises a larger range than at least one range starting at a second, lower, number of connections.

15. The system of claim 14, wherein the at least one range starting at a first number of connections comprises a smaller range than at least one range starting at a second, higher, number of connections.

16. The system of claim 11, wherein the processor assigns an indicia of a first service servicing a first number of connections to an entry in the table indexed by a first identifier selected from the second plurality of identifiers and assigns an indicia of a second service servicing a second number of connections to the entry in the table indexed by the first identifier, wherein the first number is different than the second number.

17. The system of claim 11, wherein the transmitter forwards the request to a service least recently forwarded a request, the service selected from a set of services whose indicia are stored in an entry in the table indexed by the determined identifier.

18. The system of claim 11, wherein the transmitter forwards requests to a plurality of services whose indicia are stored in the same entry in the table in a round-robin manner.

19. The system of claim 11, wherein the processor determines an updated number of active connections serviced by the service;

and assigns an indicia of the service to an entry in the table based on the updated total number.

20. A method for more efficiently load balancing services based on fewest connections by decreasing granularity of service selection as a number of fewest connections serviced by the services increases, the method comprising:

(a) establishing, by a device intermediary to a plurality of a clients and a plurality of servers, a table indexed by numbers of connections, indices in a first plurality of indices to the table each representing a predetermined number of connections and indices in a second plurality of indices to the tables each representing a predetermined range of numbers of connections;

(b) identifying, by the device, a first number of connections serviced by a first service;

(c) storing, by the device, an indicia of the first service in a first entry in the table, the first number of connections matching a predetermined number of connections represented by a first index of the first entry;

(d) identifying, by the device, a second number of connections serviced by a second service;

(e) storing, by the device, an indicia of the second service in a second entry in the table, the second number of connections falling within a predetermined range of numbers of connections represented by a second index of the second entry;

(f) detecting, by the device, a change from the first number of connections serviced by the first service to a third number of connections serviced by the first service;

(g) identifying, by the device, an index representing a predetermined number of connections or predetermined range of number of connections corresponding to the third number of connections;

(h) storing, by the device, the indicia of the first service in an entry in the table corresponding to the identified index;

(i) receiving, by the appliance, a request for a service;

(j) determining, by the appliance, an index corresponding to a fewest number of connections with at least one indicia of a service stored in an entry of the index; and

(k) forwarding, by the appliance, the request to the service corresponding to the entry of the determined index.