Clusters are sets of servers that are managed together and participate in workload management. The servers that are members of a cluster can be on different host machines, as opposed to the servers that are part of the same node and must be located on the same host machine.
Creating clusters for servers, also known as clustering servers, makes additional processing power available to your applications by distributing requests between the servers that comprise the cluster.
Servers that belong to a cluster are members of that cluster set and must all have identical application components deployed on them. Other than the applications configured to run on them, cluster members do not have to share any other configuration data. One cluster member might be running on a huge multi-processor enterprise server system, while another member of that same cluster might be running on a smaller system. The server configuration settings for each of these two cluster members are very different, except in the area of application components assigned to them. In that area of configuration, they are identical. This allows client work to be distributed across all the members of a cluster instead of all workload being handled by a single application server.
When you create a cluster, you make copies of an existing application server template. The template is most likely an application server that you have previously configured. You are offered the option of making that server a member of the cluster. However, it is recommended that you keep the server available only as a template, because the only way to remove a cluster member is to delete the server. When you delete a cluster, you also delete any servers that were members of that cluster. There is no way to preserve any member of a cluster. Keeping the original template intact allows you to reuse the template if you need to rebuild the configuration.
For more information about clusters, refer to Introduction: Clusters in the WebSphere Application Server Network Deployment information center.
For more information about establishing a clustered environment in IBM® WebSphere® Process Server, refer to Creating a clustered environment.
Last updated: Thu Apr 27 14:28:02 2006
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