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

Multiple-server bus with clustering

You can have a bus consisting of multiple servers, some or all of which are members of a cluster.

When you configure a server bus member, that server runs a messaging engine. For many purposes this is sufficient, but such a messaging engine can only run in the server it was created for. The server is therefore a single point of failure; if the server cannot run, the messaging engine is unavailable. By configuring a cluster bus member instead, the messaging engine has the ability to run in one server in the cluster, and if that server fails, the messaging engine can run in an alternative server. This is illustrated in Figure 1. For more information see Bus member types and their effect on high availability and workload sharing configuration.

Another advantage of configuring a cluster bus member is the ability to share the workload associated with a destination across multiple servers. A destination deployed to a cluster bus member is partitioned across the set of messaging engines run by the cluster servers. The messaging engines in the cluster each handle a share of the messages arriving at the destination. This is illustrated in Figure 2. This is a familiar concept to those with knowledge of cluster queues in WebSphere MQ. For more information see Workload sharing.

To summarize, with a cluster bus member you can achieve either failover, workload sharing, or both, depending on policies that you can configure. For more information about policies for messaging engines, see Policies for service integration.

Figure 1. Service integration bus with clustered serverA service integration bus with a single member - a cluster  bus member. The figure illustrates the scenario where a messaging engine has the ability to run in one server in the cluster, and if that server fails, the messaging engine can run in an alternative server.
Figure 2. Service integration bus with partitioned destinationsA service integration bus with a single member - a cluster  bus member. The figure illustrates the scenario where each server in the cluster runs a messaging engine. A bus destination is partitioned across the messaging engine running in the cluster member.
Related tasks
Planning a bus topology
Planning issues common to all bus topologies
Planning a multiple-server bus without clustering
Planning a multiple-server bus with clustering

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Last updated: 5 Oct 2005
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