Novell OPEN ENTERPRISE SERVER 2 SP 2 - CLUSTER SERVICES 1.8.7 FOR LINUX Manual page 17

The benefits that Novell Cluster Services provides can be better understood through the following
scenario.
Suppose you have configured a three-server cluster, with a Web server installed on each of the three
servers in the cluster. Each of the servers in the cluster hosts two Web sites. All the data, graphics,
and Web page content for each Web site is stored on a shared disk system connected to each of the
servers in the cluster. Figure 1-1
Three-Server Cluster
Figure 1-1
Web Server 1
Web Site A
Web Site B
During normal cluster operation, each server is in constant communication with the other servers in
the cluster and performs periodic polling of all registered resources to detect failure.
Suppose Web Server 1 experiences hardware or software problems and the users who depend on
Web Server 1 for Internet access, e-mail, and information lose their connections.
how resources are moved when Web Server 1 fails.
Three-Server Cluster after One Server Fails
Figure 1-2
Web Server 1
Web Site A
Web Site C
Web Site D
Web Site A moves to Web Server 2 and Web Site B moves to Web Server 3. IP addresses and
certificates also move to Web Server 2 and Web Server 3.
depicts how this setup might look.
Web Server 2
Web Site C
Web Site D
Fibre Channel Switch
Web Server 2
Web Site B
Web Site E
Web Site F
Fibre Channel Switch
Web Server 3
Web Site E
Web Site F
Shared Disk
System
Figure 1-2
Web Server 3
Shared Disk
System
Overview of Novell Cluster Services
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