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 a server is a member of a cluster, it allows servers to run common applications on different machines. Installing an application on a cluster that has multiple servers on different machines provides high availability. If one machine fails, the other servers in the cluster do not fail.

When you configure a server bus member, that server runs a messaging engine. For many purposes, this configuration is sufficient, but such a messaging engine can run only 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 can 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 Service integration bus with clustered server. 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. You can deploy additional messaging engines to the cluster. A destination deployed to a cluster bus member is partitioned across the set of messaging engines that the cluster servers run. The messaging engines in the cluster each handle a share of the messages arriving at the destination. This is illustrated in Service integration bus with partitioned destinations. 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 high availability (through failover). You can also configure a cluster to achieve workload sharing or workload sharing with high availability, depending on the core group policies that you configure for the messaging engines. For more information about policies for messaging engines, see Policies for service integration.

In the following figure, a service integration bus with a cluster bus member, has two application servers. One server in the cluster hosts the messaging engine, and if that server fails, the messaging engine can run in the alternative server.

Figure 1. Service integration bus with clustered server
This figure is described in the surrounding text.

In the following figure, a service integration bus with a cluster bus member, has three application servers. Each server in the cluster runs a messaging engine. A bus destination is partitioned across the messaging engines that run in the cluster member.

Figure 2. Service integration bus with partitioned destinations
This figure is described in the surrounding text.




Related concepts
Service integration high availability and workload sharing configurations
Planning issues for bus topologies
Planning issues common to all bus topologies
Planning issues for multiple-server buses without clustering
Planning issues for multiple-server buses with clustering
Bus topologies
Concept topic    

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Last updated: Aug 29, 2010 7:21:45 PM CDT
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