When you install, update, or delete an application, the updates are automatically

distributed to all members in the cluster. In WebSphere Application Server V5, if

you updated an application on a cluster, you had to stop the application on every

server in the cluster, install the update, and then restart the server. With

WebSphere Application Server V6, the Rollout Update option allows you to

update and restart the application servers on each node, one node at a time.

This provides continuous availability of the application.