Clustering transparently balances the computing load for this application’s EJB components--rule engine, scheduler, logger, Business Object Manager (BOM), workspaces and mediation. This is especially beneficial for the applications’ communication with the database storing its business data.
By default, this application supports the distribution of its processes. It distributes the load per client (not per request). Except for Mediation clustering, fail-over or high availability clustering is an optional add-on. To make a genuine highly available system, you must cluster application servers, mediation servers, and database servers (Oracle). Consult your sales representative for the licensing requirements for fail-over, or high availability clustering.
The following are some of the benefits of clustering:
• Elimination of bottlenecks and single-point failures --Clustering several servers distributes computing tasks, and enhances performance. You can even dynamically add a server to the cluster to meet increasing user demand. Replication protects your application and users’ state to ensure that the failures--like server crashes--can be fully masked from the user and application.
• Transparency to your applications and application developers--developers do not have to deal with intricacies of replication and load balancing. This means developers do not have to modify their application components to run in a clustered environment.
• Hardware and OS independence--You can use clustering across disparate hardware and operating system platforms.
In a clustered installation, when adding new users, the current web server can see the updated user list but other web servers need so execute Reindex all search indexes (in Server > Server Administration in the control panel) to see the new users.