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To increase capacity and availability, multiple portal servers can be clustered using IBM WAS Network Deployment. In a cluster the portals share a common configuration and the load is distributed evenly across all cluster instances.

WebSphere Portal comes standard with WAS Network Deployment, a distribution of IBM WAS that provides a Deployment Manager server type for centrally managing and clustering a series of servers. To cluster a series of portal servers means that all portal instances share the same configuration, including database, applications, and portlets, and site design. The cluster provides a domain against which most administrative actions are performed once and synchronized with each server in the cluster. This both simplifies administration as well as ensures that all cluster members are configured and behave identically.

A server cluster also provides a shared domain in which session and cache data can be replicated and kept consistent across all members of the cluster. The cluster also provides an application synchronization mechanism that ensures consistent application management (start, stop, updates, etc.) across the cluster.

WAS provides an HTTP Server plug-in that can balance user traffic across all members of the cluster, and through a feature called “session affinity”, ensure that a user remains bound to a specific cluster instance for the duration of their session, to improve efficiency and performance. Additionally, in the event a cluster member is down, the workload management features of the plug-in will recognize that the instance is no longer available and will route traffic around it.

There are two types of clusters: vertical and horizontal clusters. Most large-scale deployments are mixtures of both cluster types.

It is also possible to deploy multiple portal clusters to improve availability, failover, and disaster recovery.

IBM recommends that you review the cluster guidelines and limitations topics for more information about what is involved in setting up a cluster.

Parent topic:

Plan for WebSphere Portal

Related concepts

Horizontal cluster topology

Related tasks

Set up a cluster