Oracle Updated 1z0-599 Exam Questions and Answers by nella

WAN HTTP Session State Replication

Resources in a wide area network (WAN) are frequently spread across separate geographical regions. In addition to requiring network traffic to cross long distances, these resources are often separated by multiple routers and other network bottle necks. Network communication in a WAN generally has higher latency and slower interconnect.

Slower network performance within a WAN makes it difficult to use a synchronous replication mechanism like the one used within a MAN. WebLogic Server provides failover across clusters in WAN by using an asynchronous data replication scheme.

Note:

HTTP Session State Replication

Weblogic Server uses two methods for replicating HTTP session state across clusters:

in-memory replication

* Using in-memory replication, WebLogic Server copies a session state from one server instance to another. The primary server creates a primary session state on the server to which the client first connects, and a secondary replica on another WebLogic Server instance in the cluster. The replica is kept up-to-date so that it may be used if the server that hosts the servlet fails.

* JDBC-based persistence

In JDBC-based persistence, WebLogic Server maintains the HTTP session state of a servlet or JSP using file-based or JDBC-based persistence.

JDBC-based persistence is also used for HTTP session state replication within a Wide Area Network (WAN). 

Restrictions on Production Redeployment Updates

WebLogic Server can host a maximum of two different versions of an application at one time.

Note:

* When you redeploy a new version of an application, you cannot change:

An application's deployment targets

An application's security model

A Webapplicationspersistent store settings

To change any of the above features, you must first undeploy the active version of the application.

Incorrect:

* (not A)

Production redeployment enables you to update and redeploy an application in a production environment without stopping the application or otherwise interrupting the application's availability*to clients. Production redeployment saves you the trouble of scheduling application downtime, setting up redundant servers to host new application versions, manually managing client access to multiple application versions, and manually retiring older versions of an application.

* (not C) Not dependant on whether the application is JRockit or Hotspot.

* (not E)

The production redeployment strategy is supported for:

Standalone Web Application (WAR) modules and enterprise applications (EARs) whose clients access the application via a Web application (HTTP).

Enterprise applications that are accessed by inbound JMS messages from a global JMS destination, or from inbound JCA requests.

All types of Web Services, including conversational and reliable Web Services, but not 8.x Web Services.

Production redeployment is not supported for:

Standalone EJB or RAR modules. If you attempt to use production redeployment with such modules, WebLogic Server rejects the redeployment request. To redeploy such modules, remove their version identifiers and explicitly redeploy the modules.

Applications that use JTS drivers. For more information on JDBC application module limitations, see JDBC Application Module Limitations in Configuring and Managing JDBC Data Sources for Oracle WebLogic Server.

Applications that obtain JDBC data sources via the DriverManager API; in order to use production redeployment, an application must instead use JNDI to look up data sources.

Applications that include EJB 1.1 container-managed persistence (CMP) EJBs. To use production redeployment with applications that include CMP EJBs, use EJB 2.x CMP instead of EJB 1.1 CMP.