Portal, Express Beta Version 6.1 Operating systems: i5/OS, Linux,Windows

Planning your cluster

A cluster is a group of servers that provide your production environment with high availability to help ensure that your business remains active 24x7.

Read the following information to help you plan for your clustered, production environment:

• HTTP session failover
  In a clustered environment, all requests for a particular session are directed to the same server instance in the cluster. In other words, after a user establishes a session (for example, by logging in), the user is served by the same server instance for the duration of the session. To verify which server is handling user requests for a session, you can view the global settings portlet, which displays the node name of the server handling requests. If one of the servers in the cluster fails, the request is rerouted to another server in the cluster. If distributed sessions support is enabled (either by persistent sessions or memory-to-memory session replication), the new server can access session data from the database or another server instance.
• Set up an i5/OS database in a cluster
  To communicate with a database, servers running IBM^® i5/OS can use either of two JDBC drivers: the IBM Toolbox for Java JDBC driver or the IBM Developer Kit for Java JDBC driver (also referred to as the native JDBC driver). Which JDBC driver you should use depends on how you are setting up your clustered environment.
• Using external security managers in a cluster
  If you are configuring security for IBM WebSphere^® Portal Express with an external security manager, review the additional considerations described in this section, depending on the external security manager that you are using. Perform any configuration for an external security manager after you have completed all other setup, including ensuring that the WebSphere Portal Express cluster is functional.
• Cluster maintenance
  Maintaining IBM WebSphere Portal Express in a cluster typically means applying corrective services (fix packs and interim fixes) or updating the software release level on each node in the cluster. Instructions for applying corrective service to a WebSphere Portal Express cluster are provided with the corrective service package. Before applying any maintenance, it is always important to analyze any impact to your end users and ensure that you are able to provide uninterrupted service (also referred to as 24x7 availability), even during the maintenance phase.