Novell SUSE LINUX ENTERPRISE SERVER 10 SP2 HEARTBEAT Manual page 12

Suppose Web Server 1 experiences hardware or software problems and the users de-
pending on Web Server 1 for Internet access, e-mail, and information lose their connec-
tions. The following figure shows how resources are moved when Web Server 1 fails.
Figure 1.2 Three-Server Cluster after One Server Fails
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.
When you configured the cluster, you decided where the Web sites hosted on each Web
server would go should a failure occur. In the previous example, you configured Web
Site A to move to Web Server 2 and Web Site B to move to Web Server 3. This way,
the workload once handled by Web Server 1 continues to be available and is evenly
distributed between any surviving cluster members.
When Web Server 1 failed, Heartbeat software
• Detected a failure
• Remounted the shared data directories that were formerly mounted on Web server
1 on Web Server 2 and Web Server 3.
• Restarted applications that were running on Web Server 1 on Web Server 2 and
Web Server 3
• Transferred IP addresses to Web Server 2 and Web Server 3
In this example, the failover process happened quickly and users regained access to
Web site information within seconds, and in most cases, without needing to log in again.
4 Heartbeat