### To Enable Availability for the Web Container

1. In the tree component, select the desired configuration.

2. Click on Availability Service.

3. Select the Web Container Availability tab.

   Check the Availability Service box to enable availability. To disable it, uncheck the box.

4. Change other settings as described below.

   - Persistence Type: Specifies the session persistence mechanism for web applications that have availability enabled. Allowed values are `memory` (no persistence) `file` (the file system), `replicated` (memory on other servers), and `ha` (HADB).

   - Persistence Frequency: Specifies how often the session state is stored. Applicable only if the Persistence Type is `ha` or `replicated`. Allowed values are:

     - `web-method` - The session state is stored at the end of each web request prior to sending a response back to the client. This mode provides the best guarantee that the session state is fully updated in case of failure. This is the default.

     - `time-based` - The session state is stored in the background at the frequency set by the `reapIntervalSeconds` store property. This mode provides does not guarantee that session state is fully updated. However, it can provide a significant performance improvement because the state is not stored after each request.

   - Persistence Scope : Specifies how much of the session object and how often session state is stored. Applicable only if the Persistence Type is `ha` or `replicated`. Allowed values are as follows:

     - `session` - The entire session state is stored every time. This mode provides the best guarantee that your session data is correctly stored for any distributable web application. This is the default.

     - `modified-session` - The entire session state is stored if it has been modified. A session is considered to have been modified if `HttpSession.setAttribute()` or `HttpSession.removeAttribute()` was called. You must guarantee that `setAttribute()` is called every time an attribute is changed. This is not a Java EE specification requirement, but it is required for this mode to work properly.

     - `modified-attribute` - Only modified session attributes are stored. For this mode to work properly, you must follow a few guidelines:

       - Call `setAttribute()` every time the session state is modified.

       - Make sure there are no cross-references between attributes. The object graph under each distinct attribute key is serialized and stored separately. If there are any object cross references between the objects under each separate key, they are not serialized and deserialized correctly.

       - Distribute the session state across multiple attributes, or at least between a read-only attribute and a modifiable attribute.

     - Single Sign-On State: Check this box to enable persistence of the single sign-on state. To disable it, uncheck the box. For more information, see Broken Link (Target ID: ABDLN)

     - HTTP Session Store: You can change the HTTP Session Store if you changed the JDBC resource used for connections to the HADB for session persistence. For details, see `configure-ha-cluster`(1).

5. Restart the server instance.