Load balancing service for servers of a web farm

• US 8,171,385 B1
• Filed: 12/12/2008
• Issued: 05/01/2012
• Est. Priority Date: 09/14/2001
• Status: Active Grant

• Current Assignee: Cloudblue LLC
• Original Assignee: Parallels Holdings Limited (HNA Technology Co. Ltd.)
• Inventors: Tormasov, Alexander G.
• Primary Examiner(s): Riad, Amine
• Application Number:
  US12/333,685
• Time in Patent Office: 1,236 Days
• Field of Search: 714/805
• US Class Current: 714/805
• 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 67/1014 based on the content of a request

Abstract

A system for maximizing the efficiency of a load balancing server for an asymmetric web farm utilizes a TCP stack and data packets to send and receive client service requests. An internal buffer enables each web server in the web farm to balance their loading based on the contents of the client service request. Data switching between the address portion of the user space and the address portion of the kernel space within the load balancing server is eliminated.

Claims

1. A load balancing server for balancing servers in a web farm, the load balancing server comprising:

a processor;

memory;

computer code loaded into the memory for performing functions of the load balancing server, wherein the load balancing server;

receives a client request as a sequence of client TCP packets;

translates the sequence of client TCP packets to a server in a set of the servers in the web farm; and

translates a response of the server as a sequence of server TCP packets back to the client,

wherein the load balancing server calculates a checksum for a header of the client TCP packet;

calculates a checksum for a header of the translated TCP packet having a new destination address; and

generates a new checksum for the translated TCP packet, the translated TCP packet including a header and payload, the new checksum being generated by linear operations on the checksum for the client TCP packet, the checksum for the header of the client TCP packet and a checksum for the header of the translated TCP packet,

wherein the validity of the TCP packet, before and after translation, is preserved without additional verification.

2. The load balancing server of claim 1, wherein each of the servers services a specific class of the client requests based on file type of the client requests.

3. The load balancing server of claim 2, wherein a server from the set of servers that processes the client request based on contents of the client TCP packet condition.

4. The load balancing server of claim 3, wherein the balancing and translating of the client TCP packets and the server TCP packets is performed within a kernel space of the load balancing server.

5. The load balancing server of claim 4, wherein the web farm is an asymmetric web farm.

6. The load balancing server of claim 5, wherein the servers are real servers.

7. The load balancing server of claim 1, wherein the load balancing server uses functions of a TCP stack, including:

receiving an incoming connection, setting up an outgoing connection, closing a connection, receiving incoming data packets, and sending outgoing data packets.

8. The load balancing server of claim 7, wherein the load balancing server uses the functions of the TCP stack to receive a client connection.

9. The load balancing server of claim 7, wherein the load balancing server receives all the incoming data packets of the client connection by using the functions of the TCP stack.

10. The load balancing server of claim 8, wherein the load balancing server continues storing the incoming data packets of the client connection in an internal queue until the server designated to process the client request has been chosen based on contents of the incoming data packets.

11. The load balancing server of claim 9, wherein the load balancing server determines the server to respond to the client request according to preset operating rules.

12. The load balancing server of claim 10, wherein the preset operating rules include:

contents of the client service request of the internal queue;

an IP address of a client determined by titles of packets of the internal queue;

loading level of processors of web servers assigned for client service request processing; and

size of memory of the servers assigned for client request processing.

13. The load balancing server of claim 1, wherein the load balancing server creates a TCP connection to the server assigned for client service request processing by using functions of a TCP stack, the functions comprising:

receiving an incoming connection, setting up an outgoing connection,

closing a connection,

receiving incoming data packets, and

sending outgoing data packets.

14. The load balancing server of claim 1, wherein the load balancing server operates a TCP checksum packet translating algorithm for packet dispatching, wherein the TCP checksum packet translating algorithm formulates a TCP packet data checksum through a checksum of a TCP packet header.

15. The load balancing server of claim 14, wherein, to provide consistency, the load balancing server updates TCP headers of data packets and sends the data packets stored in an internal queue to the server assigned for client request processing using the TCP checksum packet translating algorithm and functions of a TCP stack.

16. The load balancing server of claim 15, wherein, to provide consistency, the load balancing server, when the connections from the client to the load balancing server and from the load balancing server to the server assigned for client service request processing are open, updates TCP headers of data packets and relocates the TCP data packets received by one of the connections to the other outgoing connection using the TCP checksum translating algorithm and functions of a TCP stack.

17. The load balancing server of claim 14, wherein the load balancing server, upon parsing the client TCP packets, modifies headers of the client TCP packets to ensure consistency of the client TCP packets.

18. The load balancing server of claim 1, wherein superusers that receive priority service from the servers are identified based on their IP address.

19. A method for balancing load of servers in a web farm, the method comprising:

receiving a client request as a sequence of client TCP packets;

translating the sequence of client TCP packets to a server in a set of servers in the web farm; and

translating a response of server as a sequence of the server TCP packets back to the client;

calculating a checksum for a header of the client TCP packet;

calculating a checksum for a header of the translated TCP packet having a new destination address;

generating a new checksum for the translated TCP packet, the translated TCP packet including a header and payload, the new checksum being generated by linear operations on the checksum for the client TCP packet, the checksum for the header of the client TCP packet and a checksum for the header of the translated TCP packet;

wherein the validity of the TCP packet, before and after translation, is preserved without additional verification.