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EP0760503A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Fault tolerant multiple network servers

Assignee: Compaq Computer Corp
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Filing: 1996-06-12
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Granted: —
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Expires: 2016-06-12
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Abstract

Abstract A fault tolerant multiple network server system in which multiple servers concurrently act as back-up servers for each other even while they are providing their own server services to the system. Rather than having an unused server monitoring for failure of a primary server and taking over control, each is act upon the network, but when its partner should fail, it assumes control of these partner servers storage subsystem. In this way, processing power of both servers is available during normal operation, but they each provide back-up capability for the other.

Inventors

  • 👤 John M. Hemphill
  • 👤 Gregory M. Stewart
  • 👤 Thomas S. Lawler

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-31 17:30
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/16; G06F11/20; G06F11/2002; G06F11/2005; G06F11/14; G06F11/1402; G06F11/1415; G06F11/142; G06F11/2007; G06F11/202; G06F11/2023; G06F11/2028; G06F11/2033; G06F11/2035; G06F11/2038; G06F11/2046; G06F11/2053; G06F11/2089; G06F11/2092; G06F13/00; G06F13/38; G06F13/40; G06F13/4004; G06F13/4022; G06F11/0703; G06F11/0751; G06F11/0754; G06F11/0757; G06F11/1479; G06F11/1482; G06F11/22

Claims Analysis

Total Claims: 13
Claim 1
Independent Claim 250 words
A dual fault tolerant active server system for a network, the system comprising: a first active server for connection to the network, said first active server providing a first indication that it is functioning properly; a second active server for connection to the network, said second active receiving said first indication from said first active server and server providing a second indication that it is functioning properly to said first active server, wherein said first active server provides a first switch command when said second active server fails to provide said second indication that said second active server is functioning properly and wherein said second active server provides a second switch command when said first active server fails to provide said first indication that said first active server is functioning properly; a first storage system with a first storage media, said first storage system primarily coupling said first storage media to said first active server and alternatively coupling said first storage media to said second active server and decoupling said first storage media from said first active server upon receipt of said second switch command from said second active server; and a second storage system with a second storage media, said second storage system primarily coupling said second storage media to said second active server and alternatively coupling said second storage media to said first active server and decoupling said second storage media from said second active server upon receipt of said first switch command from said first active server.
Claim 2
Dependent Claim 82 words
The system of claim 1, further comprising: a first SCSI bus connecting said first active server with said second storage system, and wherein said first switch command comprises a series of SCSI reset signals over said first SCSI bus from said first active server; and a second SCSI bus connecting said second active server with said first storage system, and wherein said second switch command comprises a series of SCSI reset signals over said second SCSI bus from said second active server.
Claim 3
Dependent Claim 29 words
The system of claim 1, further comprising: a serial interconnect between said first active server and said second active server, said serial interconnect carrying said first and second indications.
Claim 4
Dependent Claim 19 words
The system of claim 1, wherein said first and second indications are provided to and received from the network.
Claim 5
Dependent Claim 44 words
The system of claim 1, wherein said first active server further includes: a recovery agent service that sends a heartbeat message to said second active server as said first indication and receives a heartbeat message from said second active server as said second indication.
Claim 6
Dependent Claim 20 words
The system of claim 5, wherein said heartbeat messages include a ping heartbeat message and a normal shutdown heartbeat message.
Claim 7
Dependent Claim 93 words
The system of claim 1, wherein said first active server and said second active server run registered applications, wherein upon failure of said second active server to provide the indication that said second active server is functioning properly, said first active server sends a predetermined message to said registered applications in said first active server, and wherein upon failure of said first active server to provide the indication that said first active server is functioning properly, said second active server sends the predetermined message to said registered applications in said second active server.
Claim 8
Dependent Claim 32 words
The system of claim 1, wherein said first active server includes software for checking data integrity of said second storage medium after providing said first switch command to said second storage system.
Claim 9
Dependent Claim 88 words
An active server for use with a partner active server in a network, the active server comprising: a connection for a first storage system; a recovery agent for providing and receiving heartbeat messages to and from the partner active server, said recovery agent sending a switch command upon a failure to receive the-heartbeat message from the partner active server; and a connection for a second storage system, the second storage system providing data to the active server upon receipt by the second storage system of said switch command.
Claim 10
Dependent Claim 34 words
The active server of claim 9, further comprising: registered applications, said recovery agent sending a predetermined message to said registered applications upon a failure of the partner active server to send the heartbeat message.
Claim 11
Dependent Claim 215 words
A multiple active backup server system for a network, the system comprising: a first active server; a second active server; a third active server, wherein said first active server, said second active server, and said third active server send and receive heartbeat messages to and from each other, wherein upon failure of said first active server to send said heartbeat message, said second active server provides a second switch command, wherein upon failure of said second active server to send said heartbeat message, said third active server provides a third switch command, and wherein upon failure of said third active server to send said heartbeat message, said first active server provides a first switch command; a first storage system primarily coupled to said first active server and alternatively coupled to said second active server and decoupled from said first active server upon receipt of said second switch command; a second storage system primarily coupled to said second active server and alternatively coupled to said third active server and decoupled from said second active server upon receipt of said third switch command; and a third storage system primarily coupled to said third active server and alternatively coupled to said first active server and decoupled from said third active server upon receipt of said first switch command.
Claim 12
Independent Claim 186 words
A method of providing active backup between a first active server and a second active server, the first active server having a first storage system that is switchable to the second active server, and the second active server having a storage system that is switchable to the first active server, the method comprising the steps of: providing data from the first storage system through the first active server to the network; providing data from the second storage system through the second active server to the storage system; providing an indication from the first active server to the second active server that the first active server is functioning properly; providing an indication from the second active server to the first active server that the second active server is functioning properly; and upon a failure of the first active server to receive the indication from the second active server that the second active server is functioning properly, switching the second storage system from the second active server to the first active server, and providing data from the second storage system through the first active server to the network.
Claim 13
Dependent Claim 66 words
The method of claim 12, further comprising the step of: upon a failure of the second active server to receive the indication from the first active server that the first active server is functioning properly, switching the first storage system from the first active server to the second active server, and providing data from the first storage system through the second active server to the network.

References Cited (Backward Citations)

EP0342021A2 Cited
US5423026A Cited
EP0709779A2 Cited

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