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

Highly available messaging engine configuration

This configuration consists of a single messaging engine, running in a cluster, which can failover to one or more alternative servers.

This configuration can be achieved by adding a cluster to the service integration bus. The default policy will allow the messaging engine to failover between servers in the cluster, making the messaging engine highly available. You can optionally give the messaging engine a preference for one or more servers, by adding preferred servers to the policy. You can further alter the policy to control the availability characteristics of the messaging engine, as described in Configuring a policy for messaging engines.

There is no workload sharing in this configuration as there is only one messaging engine to handle the traffic through the destination.

The diagram below shows a highly available messaging engine configuration in which the single messaging engine, ME, with data store DS, is running in a cluster of three servers. When Server-1 fails the messaging engine is failed over and continues to run on Server-2.

Figure 1. Highly available messaging engine configuration before loss of Server-1The messaging engine is running in Server-1.
Figure 2. Highly available messaging engine configuration after loss of Server-1Server-1 has failed and the messaging engine has been moved to Server-2.

Each server in the cluster contains the definition of the messaging engine, and creates an instance of the messaging engine so that the instance is ready to be activated if another server should fail.

The data store for the messaging engine must be accessible by all the servers in the cluster. The means of achieving this is dependent on the data store topology used. If you are using a networked database server then you need to ensure that it is accessible from all servers in the cluster that may run the messaging engine. Alternatively, you could use an external high availability framework to manage the database using a shared disk.

You can specify one or more preferred servers for the messaging engine, as mentioned above. Whenever a preferred server is available the HAManager will run the messaging engine in it. When no preferred server is available the messaging engine will run in an alternative server. When a preferred server once again becomes available the HAManager will move the messaging engine back to it if, and only if, the Fail back option is set on the policy.


Concept topic

Terms of Use | Feedback

Last updated: 5 Oct 2005
http://publib.boulder.ibm.com/infocenter/ws60help/index.jsp?topic=/com.ibm.websphere.pmc.nd.doc\concepts\cjt0010_.html

© Copyright IBM Corporation 2004, 2005. All Rights Reserved.
This information center is powered by Eclipse technology. (http://www.eclipse.org)