SYSTEMS AND METHODS FOR PROVIDING DYNAMIC CONNECTION SPILLOVER AMONG VIRTUAL SERVERS

• US 20080049616A1
• Filed: 08/22/2006
• Published: 02/28/2008
• Est. Priority Date: 08/22/2006
• Status: Active Grant

• Current Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Original Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Inventors: Shetty, Anil, Kamath, Sandeep, Verzunov, Sergey, Suganthi, Josephine
• Granted Patent: US 8,493,858 B2
• Time in Patent Office: Days
• US Class Current: 370/235
• CPC Class Codes: H04L 43/16 Threshold monitoring
• 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 67/1012 based on compliance of requirements or conditions with available server resources
• CPC Class Codes: H04L 67/1029 using data related to the state of servers by a load balancer
• CPC Class Codes: H04L 67/1031 Controlling of the operation of servers by a load balancer, e.g. adding or removing servers that serve requests

Abstract

A method for an appliance to switch handling of transport layer connection requests from a first virtual server of the appliance managing a first plurality of services to a second virtual server of the appliance managing a second plurality of services upon exceeding, by the first virtual server, a maximum connection threshold determined dynamically from a status of the first plurality of services. The method includes the steps of: establishing, on an appliance, a first virtual server which directs transport layer connection requests from a plurality of clients to a first plurality of services; establishing, via the appliance, a predetermined threshold identifying a maximum active transport layer connection capacity for the first virtual server, the predetermined threshold comprising a sum of a predetermined connection capacity for each of the plurality of services; monitoring, by the appliance, a status for each of the plurality of services; determining, by the appliance, the status of a service of the plurality of services indicates the service is not available; and adjusting, by the appliance in response to the determination, the predetermined threshold to comprise the sum of the predetermined connection capacity for each of the plurality of services having a status of available. Corresponding systems are also described.

Claims

1. A method for an appliance to direct handling of transport layer connection requests from a first virtual server of the appliance managing a first plurality of services to a second virtual server of the appliance managing a second plurality of services upon exceeding, by the first virtual server, a maximum connection threshold determined dynamically from a status of the first plurality of services, the method comprising the steps of:

(a) establishing, on an appliance, a first virtual server which directs transport layer connection requests from a plurality of clients to a first plurality of services;

(b) establishing, via the appliance, a predetermined threshold identifying a maximum active transport layer connection capacity for the first virtual server, the predetermined threshold comprising a sum of a predetermined connection capacity for each of the plurality of services;

(c) monitoring, by the appliance, a status for each of the plurality of services;

(d) determining, by the appliance, the status of a service of the plurality of services indicates the service is not available; and

(e) adjusting, by the appliance in response to the determination, the predetermined threshold to comprise the sum of the predetermined connection capacity for each of the plurality of services having a status of available.

2. The method of claim 1, further comprising the step of determining, by the appliance, a number of active connections to the first virtual server exceeds the predetermined threshold.

3. The method of claim 2, further comprising the step of establishing, by the appliance in response to the determination, a second virtual server which directs transport layer connection requests from a plurality of clients to a second plurality of services.

4. The method of claim 2, further comprising the steps of receiving, by the appliance, a transport layer connection request from a first client, and providing, by the appliance, the transport layer connection request to a second virtual server which directs transport layer connection requests from a plurality of clients to a second plurality of services.

5. The method of claim 4, further comprising the step of determining, by the appliance, a number of active connections to the second virtual server exceeds a predetermined threshold.

6. The method of claim 4, further comprising the steps of:

(f) determining, by the appliance, a number of active connections to the first virtual server has fallen below the predetermined threshold;

(g) receiving, by the appliance, a second transport layer connection request from a second client; and

(h) providing, by the appliance, the second transport layer connection request to the first virtual server.

7. The method of claim 4, further comprising the steps of:

(f) determining, by the appliance, a number of active connections to the first virtual server has fallen below the predetermined threshold;

(g) receiving, by the appliance, a second transport layer connection request from the first client;

(h) identifying, by the appliance, an existing connection between the first client and the second virtual server; and

(i) providing, by the appliance responsive to the identification, the second transport layer connection request to the second virtual server.

8. The method of claim 1, wherein step (c) comprises monitoring, by the appliance using a plurality of monitoring agents, a status for each of the plurality of services.

9. The method of claim 1, wherein step (c) comprises monitoring, by the appliance using a plurality of monitoring agents, a status for each of the plurality of services, wherein each monitoring agent of the plurality of monitoring agents has an assigned weight.

10. The method of claim 9, wherein step (d) comprises determining, by the appliance, a sum of the assigned weights for each of the plurality of monitoring agents is below a given threshold.

11. The method of claim 1, wherein step (d) comprises determining, by the appliance, a deviation of a response time of a service of the plurality of services exceeds a given threshold, wherein the deviation is the deviation of the response time from an average response time for the service.

12. The method of claim 1, wherein step (d) comprises determining, by the appliance, a deviation of a response time of a service of the plurality of services exceeds a given threshold, wherein the deviation is the deviation of the response time from a dynamically computed average response time for the service.

13. The method of claim 1, wherein step (e) comprises subtracting, by the appliance, the predetermined connection capacity for the unavailable service from the predetermined threshold.

14. A computer implemented system to direct handling of transport layer connection requests from a first virtual server of the appliance managing a first plurality of services to a second virtual server of the appliance managing a second plurality of services upon exceeding, by the first virtual server, a maximum connection threshold determined dynamically from a status of the first plurality of services, the system comprising:

a network appliance which establishes a first virtual server that directs transport layer connection requests from a plurality of clients to a first plurality of services;

establishes, a predetermined threshold identifying a maximum active transport layer connection capacity for the first virtual server, the predetermined threshold comprising a sum of a predetermined connection capacity for each of the plurality of services;

monitors a status for each of the plurality of services;

determines the status of a service of the plurality of services indicates the service is not available; and

adjusts in response to the determination, the predetermined threshold to comprise the sum of the predetermined connection capacity for each of the plurality of services having a status of available.

15. The system of claim 14, wherein the appliance determines a number of active connections to the first virtual server exceeds the predetermined threshold.

16. The system of claim 15, wherein the appliance establishes, in response to the determination, a second virtual server which directs transport layer connection requests from a plurality of clients to a second plurality of services.

17. The system of claim 15, wherein the appliance receives a transport layer connection request from a first client, and provides the transport layer connection request to a second virtual server which directs transport layer connection requests from a plurality of clients to a second plurality of services.

18. The system of claim 17, wherein the appliance determines a number of active connections to the second virtual server exceeds a predetermined threshold.

19. The system of claim 17, wherein the appliance determines a number of active connections to the first virtual server has fallen below the predetermined threshold;

receives a second transport layer connection request from a second client; and

provides the second transport layer connection request to the first virtual server.

20. The system of claim 17, wherein the appliance determines a number of active connections to the first virtual server has fallen below the predetermined threshold;

receives a second transport layer connection request from the first client;

identifies an existing connection between the first client and the second virtual server; and

provides, responsive to the identification, the second transport layer connection request to the second virtual server.

21. The system of claim 14, wherein the appliance determines, using a plurality of monitoring agents, a status for each of the plurality of services.

22. The system of claim 14, wherein the appliance determines, using a plurality of monitoring agents, a status for each of the plurality of services, wherein each monitoring agent of the plurality of monitoring agents has an assigned weight.

23. The system of claim 22, wherein the appliance determines a sum of the assigned weights for each of the plurality of monitoring agents is below a given threshold.

24. The system of claim 14, wherein the appliance determines a deviation of a response time of a service of the plurality of services exceeds a given threshold, wherein the deviation is the deviation of the response time from an average response time for the service.

25. The system of claim 14, wherein the appliance determines a deviation of a response time of a service of the plurality of services exceeds a given threshold, wherein the deviation is the deviation of the response time from a dynamically computed average response time for the service.

26. The system of claim 14, wherein the appliance subtracts the predetermined connection capacity for the unavailable service from the predetermined threshold.