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Copyright © TIBCO Software Inc. All Rights Reserved


Chapter 1 Concepts : Overview

Overview
A cluster is a group of machines that work together as a single system to ensure that applications and resources are available at all times. The machines are managed as a single system using cluster software, which provides a way to support fault-tolerance, high-availability, scalability, and so on.
The computers are physically connected by cables and programmatically connected by cluster software. These connections allow computers to use failover and load balancing, which is not possible with a stand-alone computer.
Figure 1 shows a failover cluster solution. The nodes in a cluster are configured with a shared drive. The cluster software manages access to the shared drive so that only applications on a single machine use a particular resource at anytime.
The failover cluster solution primarily provides uninterrupted service in the event of a failure within the cluster. This solution is commonly used for database applications.
Applications that are deployed to a failover cluster can be managed under cluster software. Applications are under the control of cluster software, which ensures that only one application runs at once on one of the cluster machines. This kind of application is in active-passive mode.
Figure 1 Failover Cluster Solution
Cluster Aware and Cluster Unaware Applications
A cluster environment supports two types of applications: cluster-aware applications and cluster-unaware applications.
Cluster software manages cluster-unaware applications by using basic methods for failure detection and application shutdown. For example, the Microsoft Cluster Server solution manages cluster-unaware software as a generic application resource type.
High-availability Modes
High-availability applications can be categorized to different modes, hot standby, warm standby, and cold standby in a cluster.
Basic Cluster Terminology
The following basic terminology is used in this document.

Copyright © TIBCO Software Inc. All Rights Reserved
Copyright © TIBCO Software Inc. All Rights Reserved