The replicated persistence type uses other servers in the cluster for session persistence. Clustered server instances replicate session state in a ring topology. Each backup instance stores the replicated data in memory. This allows sessions to be distributed. For details, see Distributed Sessions and Persistence. In addition, you can configure the frequency and scope of session persistence. The other servers are also used as the passivation and activation store. Use this option in a production environment that requires session persistence.
Some topics in the documentation pertain to features that are available only in domains that are configured to support clusters. Examples of domains that support clusters are domains that are created with the cluster profile or the enterprise profile. For information about profiles, see Usage Profiles in Sun Java System Application Server 9.1 Administration Guide.
To use the replicated persistence type, you must enable availability. Select the Availability Service component under the relevant configuration in the Admin Console. Check the Availability Service box. To enable availability for the web container, select the Web Container Availability tab, then check the Availability Service box. All instances in an Application Server cluster should have the same availability settings to ensure consistent behavior. For details, see the Sun Java System Application Server 9.1 High Availability Administration Guide.
To change settings such as persistence frequency and persistence scope for the entire web container, use the Persistence Frequency and Persistence Scope drop-down lists on the Web Container Availability tab in the Admin Console, or use the asadmin set command. For example:
asadmin set server-config.availability-service.web-container-availability.persistence-frequency=time-based
For more information, see the description of the asadmin set command in the Sun Java System Application Server 9.1 Reference Manual.
To specify the replicated persistence type for a specific web application, edit the sun-web.xml file as in the following example. Note that persistence-type must be set to replicated. This overrides the web container availability settings for the web application.
<sun-web-app> ... <session-config> <session-manager persistence-type=replicated> <manager-properties> <property name=persistenceFrequency value=web-method /> </manager-properties> <store-properties> <property name=persistenceScope value=session /> </store-properties> </session-manager> ... </session-config> ... </sun-web-app>
The replicated persistence type supports all the manager properties listed under manager-properties in Sun Java System Application Server 9.1 Application Deployment Guide except sessionFilename, and supports the persistenceScope store property listed under store-properties in Sun Java System Application Server 9.1 Application Deployment Guide.
For more information about the sun-web.xml file, see The sun-web.xml File in Sun Java System Application Server 9.1 Application Deployment Guide.