WebSphere WebSphere Application Server Network Deployment, Version 6.1.x Operating Systems: AIX, HP-UX, i5/OS, Linux, Solaris, Windows, z/OS

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 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 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.

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 concepts
Service integration high availability and workload sharing configurations
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

Concept topic

Terms of use | Feedback


Timestamp icon Last updated: 26 February 2009
http://publib.boulder.ibm.com/infocenter/wasinfo/v6r1/index.jsp?topic=/com.ibm.websphere.pmc.nd.multiplatform.doc/concepts/cjj0072_.html

Copyright IBM Corporation 2004, 2009. All Rights Reserved.
This information center is powered by Eclipse technology. (http://www.eclipse.org)