Oracle 1z0-599 Dumps

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). 

Oracle WebLogic Server Logging Last Resource (LLR) An additional option for XA transactions is Oracle WebLogic Server’s Logging Last Resource (LLR) transaction optimization through JDBC data sources. LLR is a performance enhancement option that enables one non-XA resource to participate in a distributed transaction with the same ACID guarantee asXA. In a distributed transaction with an LLR participant, the Oracle WebLogic Server transaction

Note:

*A multi data source can be thought of as a pool of data sources. Multi data sources are best used for failover or load balancing between nodes of a highly available database system, such as redundant databases or Oracle Real Application Clusters (Oracle RAC).

* (not B)A single GridLink data source provides connectivity between WebLogic Server and an Oracle Database service, which may include multiple Oracle RAC clusters

* High Availability Storage Solutions

If you have applications that need access to persistent stores that reside on remote machines after the migration of a JMS server or JTA transaction log, then you should implement one of the following highly-available storage solutions:

/ File-based stores (default or custom)—Implement a hardware solution, such as a dual-ported SCSI disk or Storage Area Network (SAN) to make a file store available from shareable disks or remote machines.

/ JDBC-accessible stores—Configure a JDBC store or JDBC TLOG store and use JDBC to access this store, which can be on yet another server. Applications can then take advantage of any high-availability or failover solutions offered by your database vendor. In addition, JDBC stores support GridLink data sources and multi data sources, which provide failover between nodes of a highly available database system, such as Oracle Real Application Clusters (Oracle RAC).