Reliability and availability of distributed servers

• US 8,364,815 B2
• Filed: 10/03/2005
• Issued: 01/29/2013
• Est. Priority Date: 03/18/2005
• Status: Active Grant

• Current Assignee: Riverbed Technology, LLC (Riverbed Technology Incorporated)
• Original Assignee: Riverbed Technology Incorporated
• Inventors: Burman, Daniel Edwin, Subbanna, Kartik, McCanne, Steven, Wu, David Tze-Si, Day, Mark Stuart
• Primary Examiner(s): Moore, Ian N
• Assistant Examiner(s): TOWFIGHI, AFSHAWN M
• Application Number:
  US11/243,068
• Publication Number:
  US 20060212935A1
• Time in Patent Office: 2,675 Days
• Field of Search: 709223-226, 709238-244
• US Class Current: 709/225
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04L 67/2876 Pairs of inter-processing entities at each side of the network, e.g. split proxies
• CPC Class Codes: H04L 67/563 Data redirection of data network streams
• CPC Class Codes: H04L 67/568 Storing data temporarily at an intermediate stage, e.g. caching

Abstract

A system of network proxies distributes data to multiple servers. Each network proxy is associated with a server. A network proxy intercepts a client request for data. If the network proxy determines that the request can be served using a copy of data stored on the local server, rather than the data stored on a remote server, it diverts the request to the local server. If the network proxy determines that the request cannot be served using a data from the local server, the network proxy diverts the request to a remote server storing the primary copy of the data. A server map specifies the locations of the primary copies of data. When a primary copy of data is updated on one of the servers, the associated network proxy propagates the updated data to the other servers. The servers can provide data from files, e-mail services, databases, or multimedia services.

Claims

1. A distributed system comprising:

a first network proxy adapted to interface with a first client and a first server that is local to the first network, wherein the first network proxy is connected to the first client;

a second network proxy adapted to interface with the first network proxy via a network connection and adapted to interface with a second client and a second server, wherein the second network proxy is connected to the second client;

wherein the first network proxy includes;

first logic, adapted to determine the operational status of the network connection between the first network proxy and the second network proxy;

second logic, adapted to receive a request for first data from the first client; and

third logic, adapted to respond to the request by retrieving first data, or a representation thereof, from the second server via the second network proxy if the first logic determined that the network connection between the first network proxy and the second network proxy was operational;

wherein the third logic is further configured to respond to the request, by retrieving the first data or the representation thereof, from the first server if the first logic determined that the network connection was not operational;

wherein the second network proxy includes;

fourth logic, adapted to determine the operational status of the network connection between the first network proxy and the second network proxy;

fifth logic, adapted to receive a second request for second data from the second client;

sixth logic, adapted to respond to the second request by retrieving second data, or a representation thereof, from the first server via the first network proxy if the fourth logic determined that the network connection between the first proxy and the second proxy was operational;

wherein the sixth logic is further configured to respond to the second request by retrieving the second data of the representation thereof, from the second server if the fourth logic determined that the network was not operational.

2. The distributed system of claim 1, wherein the first data or representation thereof retrieved from the first server is a read-only copy of the first data that cannot be modified by the first client.

3. The distributed system of claim 1, wherein the second data or representation thereof retrieved from the second server is a read-only copy of the second data that cannot be modified by the second client.

4. The distributed system of claim 1, wherein:

the first network proxy includes logic adapted to communicate with the first client and the first server via a first local area network;

the second network proxy includes logic adapted to communicate with the second server via a second local area network; and

the network connection includes a wide area network.

5. The distributed system of claim 1, wherein the first network proxy includes a transaction accelerator.

6. The distributed system of claim 1, wherein the first server is one or more of a file server, an e-mail server, a multimedia server, a database server, or a web server.

7. The distributed system of claim 1, wherein the second server is one or more of a file server, an e-mail server, a multimedia server, a database server, or a web server.

8. A distributed system comprising:

a first network proxy adapted to interface with a first client and a first server that is local to the first network proxy, wherein the first network proxy is connected to the client;

a second network proxy adapted to interface with the first network proxy via a network connection and adapted to interface with a second server that is local to the second network proxy, wherein the second network proxy is connected to the second server;

wherein the first network proxy includes;

first logic, adapted to determine the operational status of the network connection between the first network proxy and the second network proxy;

second logic, adapted to receive a first request for first data from the first client; and

third logic, adapted to respond to the first request, at least when the request is addressed to the second server, by;

in response to the first logic determining that the network connection between the first proxy and the second proxy is not operational, retrieving a copy of the first data from the first server, and then sending the copy of the first data to the first client;

wherein the second logic is further adapted to receive a second request for second data from the first client;

wherein third logic is further adapted to respond to the second request, at least when the request is addressed to the second server, by;

in response to the first logic determining that the network connection between the first proxy and the second proxy is operational, retrieving the second data from the second server, even if the first server has a local copy of the second data, and then sending the second data to the first client;

wherein the second logic is further adapted to receive a third request for third data from the first client;

wherein third logic is further adapted to respond to the third request, at least when the request is addressed to the second server, by;

in response to the first logic determining that the network connection between the first proxy and the second proxy is not operational and that the first server does not have a copy of the third data, retrieving a broadcast copy of the third data from the first server and then sending the broadcast copy of the third data to the first client.

9. The distributed system of claim 8, wherein the second network proxy is adapted to interface with a second client and includes logic adapted to determine the operational status of the network connection between the first network proxy and second network proxy, logic adapted to receive a fourth request for fourth data from the second client, and logic adapted to respond to the fourth request by retrieving fourth data from the first server via the first network proxy in response to a determination that the network connection is operational and by retrieving a copy of the fourth data from the second server in response to a determination that the network connection is not operational.

10. The distributed system of claim 9, wherein the second data or representation thereof retrieved from the second server is a read-only copy of the second data that cannot be modified by the second client.

11. The distributed system of claim 8, wherein the first data or representation thereof retrieved from the first server is a read-only copy of the first data that cannot be modified by the first client.

12. The distributed system of claim 8, wherein:

the first network proxy includes logic adapted to communicate with the first client and the first server via a first local area network;

the second network proxy includes logic adapted to communicate with the second server via a second local area network; and

the network connection includes a wide area network.

13. The distributed system of claim 8, wherein the first network proxy includes a transaction accelerator.

14. The distributed system of claim 8, wherein the first server is one or more of a file server, an e-mail server, a multimedia server, a database server, or a web server.