7.1.1 Overview of a cluster system (for Windows)

A cluster system consists of a primary server being used to execute processing and a secondary server that will inherit processing in the event of a failure. If a failure occurs, processing is transferred from the primary node to the secondary node to prevent interruption of jobs, thereby improving availability. Transferring processing in the event of a failure is called failover.

The software that controls the entire cluster system is called the cluster software. The cluster software monitors system operations and executes failover in the event of a failure in order to prevent interruption of jobs.

Figure 7‒2: Access after failover during normal operation

To enable an application such as JP1/IM - Manager to perform failover, you must run the application on a logical host. A logical host is a logical server unit for failover that is controlled by the cluster software. The logical host uses a logical host name and has a shared disk and a logical IP address that can be inherited from the primary node to the secondary node. Applications that run on the logical host store data on the shared disk and use the logical IP address for communication so that they can execute failover without having to depend on the physical servers.

Running JP1/IM - Manager in the logical host environment of a cluster system is called cluster operation.

Note

About the term logical host

This manual uses the term logical host to designate a failover unit. Some cluster software and applications use the term group or package. Check your cluster software manual for the corresponding term.

As opposed to the logical host that is the failover unit, a physical server is called a physical host. The host name used by the physical host (host name that is displayed when the hostname command is executed) is called a physical host name, and the IP address that corresponds to the physical host name is called the physical IP address. For the disk, a physical host uses the local disk. This disk is specific to the server and cannot be inherited to any other server.

To Page Top