Static clusters in a WebSphere® Application Server Network Deployment configuration are different from the dynamic clusters that you can define in WebSphere Extended Deployment. Both types of clusters support workload balancing, however, dynamic clusters are controlled by autonomic managers that can optimize the performance of the cluster.
Characteristic | Static clusters | Dynamic clusters |
---|---|---|
Cluster management | You define the application servers that are in the static cluster and then start or stop all the application servers in the cluster. | A dynamic cluster can start and stop instances of application servers as required. If the dynamic cluster is in automatic mode, then the application server instances stop and start automatically. If the dynamic cluster is in supervised mode, then WebSphere Extended Deployment advises the administrator to start and stop application servers at certain times. In manual mode, the administrator decides when instances of application servers are stopped and started. |
Cluster templates | When you define a static cluster, you can select an application server template on which to base all the application server instances that you create. However, any changes that you make to the template after creating the instances do not change the instances. | When you define a dynamic cluster, you can define an application server template for the application server instances. If you make a change to the dynamic cluster, then the changes are propagated to all of the application server instances. You cannot change the template. |
Application server weights | You explicitly assign a weight value to each application server instance. You can also enable the dynamic workload manager to assign weight values. To enable the dynamic workload manager, click Servers > Clusters > cluster_name > Dynamic WLM. | The dynamic workload manager is enabled by default and assigns weights to the application server instances. To disable the dynamic workload manager, click Servers > Dynamic Clusters > dynamic_cluster_name > Dynamic WLM. |
Applicability | You can use static clusters in a WebSphere Application Server Network Deployment environment, or a WebSphere Extended Deployment environment. If you use static clusters in a WebSphere Extended Deployment environment, then the behavior is identical to static clusters in a WebSphere Application Server Network Deployment environment. | You can use dynamic clusters in a WebSphere Extended Deployment environment only. |