WebSphere WebSphere Application Server Network Deployment, Version 6.0.x Operating Systems: AIX, HP-UX, Linux, Solaris, Windows

Bus member types and their effect on high availability and workload sharing configuration

You can add either a server or a cluster to a service integration bus, to create either a server bus member or a cluster bus member.

Adding a server to a bus

When you add a server to a service integration bus, a messaging engine is created automatically. This single messaging engine cannot participate in workload sharing with other messaging engines; it can only do that in a cluster. The messaging engine also cannot be highly available, since there are no other servers in which it can run.

Adding a cluster to a bus

When you add a server cluster to a service integration bus, a single messaging engine is created automatically; you can then add further messaging engines if required. The rest of the information in this topic applies only to cluster bus members.

A cluster deployment can provide workload sharing, availability, or both, depending on the number of messaging engines in the cluster and the policy bound to each messaging engine's HAGroup.

If there is only one messaging engine in the cluster and you deploy a destination to the same cluster, the destination will be localized by that messaging engine. The destination will not be partitioned and all messaging workload for that destination will be handled by that messaging engine; it cannot be shared. The availability characteristics of the destination will be the same as the availability characteristics of the messaging engine.

You can benefit from increased scalability by introducing additional messaging engines to the cluster. When you deploy a destination to the cluster it will be localized by all the messaging engines within the cluster and the destination will become partitioned across the messaging engines. The messaging engines will now share all traffic passing through the destination, reducing the impact of one messaging engine failing. The availability characteristics of each destination partition will be the same as the availability characteristics of the messaging engine the partition is localized by.

You control the availability behavior of each messaging engine by modifying the policy that the HAManager applies to the messaging engine's HAGroup. See Policies for service integration for more information.

Related concepts
Bus topologies
Related tasks
Adding a server as a new bus member
Adding a cluster as a member of a bus
Adding a messaging engine to a cluster

Concept topic

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Last updated: 15 Mar 2007
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