Sun Java System Application Server Enterprise Edition 8.1 2005Q2 Developer's Guide

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### The ha Persistence Type

The ha persistence type uses the high-availability database (HADB) for session persistence. The HADB 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 HADB is also used as the passivation and activation store. Use this option in a production environment that requires session persistence.

The HADB must be configured and enabled before you can use distributed sessions. For configuration details, see the description of the `configure-ha-cluster` command in the Sun Java System Application Server Enterprise Edition 8.1 2005Q2 Reference Manual.

To enable the HADB, select the Availability Service component under the relevant configuration in the Administration Console. Check the Instance Level Availability box. To enable availability for the web container, select the Web Container Availability tab, then check the Availability Service box. For details, see the Sun Java System Application Server Enterprise Edition 8.1 2005Q2 High Availability Administration Guide.

To change settings such as persistence frequency and persistence scope for the entire web container, see the description of the `configure-ha-persistence` command in the Sun Java System Application Server Enterprise Edition 8.1 2005Q2 Reference Manual.

To specify the `ha` 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 `ha`. This overrides the web container availability settings for the web application.

    <sun-web-app>
    ...
    <session-config>
    	<session-manager persistence-type=fileha>
    		<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 `ha` persistence type supports all the manager properties listed under manager-properties except `sessionFilename`, and supports the `persistenceScope` store property listed under store-properties.

For more information about the `sun-web.xml` file, see The sun-web.xml File.

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