High Availability Manager (HAManager)
IBM WAS ND V6 introductes High Availability Manager (HAManager), which... ...
- Enhances the availability of singleton services in WebSphere
- Provides group services and group messaging capabilities to WebSphere internal components.
Singleton services include:
The HAManager runs as a service within each appserver process (Deployment Manager, Node Agents, or appservers) that monitors the health of WebSphere clusters. In the event of a server failure, the HAManager will failover any singleton services that were running on the server that just failed. Examples of such services would include the recovery of any in-flight transactions and/or restarting any messaging engines that were running there. As depicted in Figure 9-1, each appserver process runs a HAManager component and shares information through the underlying communication infrastructure Distribution and Consistency Services (DCS) such that no single point of failure will exist in the topology. Every member in a WebSphere cluster knows where singleton services are running.
Figure 9-1 Architecture of a single core group configuration
WebSphere V6 uses a peer-to-peer hot failover model that dramatically improves recovery time. By leveraging Network Attached Storage technology, WebSphere clusters can be made highly available with a simpler setup. No external high availability software is required.
Deployment Managers and Node Agents cannot be made highly available with HAManager. Refer to the redbook WAS ND V6: High availability solutions, SG24-6688 for information about how to achieve this.