availability-enabled

true

(optional) If set to true, and if availability is enabled for the server instance (see availability-service), high-availability features apply to all web applications deployed to the server instance that do not have availability disabled. All instances in a cluster should have the same availability value to ensure consistent behavior.

persistence-type

memory (availability disabled)

replicated (availability enabled)

(optional) Specifies the session persistence mechanism for web applications that have availability enabled. Allowed values are memory (no persistence), file (the file system) and replicated (other servers).

If set to memory, the manager-properties element’s session-file-name attribute specifies the file system location where the HTTP session state is stored if the server instance is gracefully shut down. This is useful for internal testing but is not supported for production environments.

If set to file, the store-properties element’s directory attribute specifies the file system location where the HTTP session state is stored. Persisting to the file system is useful for internal testing but is not supported for production environments.

persistence-frequency

web-method

(optional) Specifies how often the session state is stored. Applicable only if the persistence-type is replicated. Allowed values are as follows:

• 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.

• time-based - The session state is stored in the background at the frequency set by the manager-properties element’s reap-interval-in-seconds attribute. This mode provides less of a guarantee that the session state is fully updated. However, it can provide a significant performance improvement because the state is not stored after each request.

persistence-scope

session

(optional) Specifies how much of the session state is stored. Applicable only if the persistence-type is 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.

• 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 some guidelines, which are explained immediately following this table.

sso-failover-enabled

false

(optional) If true, the single sign-on state is highly available. To enable single sign-on, use the sso-enabled property of the virtual-server element.