Transparent Application Failover (TAF).Connection failover ensures that an open route to your data is always available, even when server downtime occurs. If a connection failure occurs at connect time, the application can fail over the connection to another active node in the cluster. Oracle RAC systems provide two methods of failover to provide reliable access to data: The following example shows connection information in a tnsnames.ora file configured for an Oracle RAC system identified by the net service name entry, ARMSTRONG.ACCT. In a tnsnames.ora file, connection information for Oracle services is associated with a net service name. Connection failover and client load balancing instructions.Server process type (shared or dedicated).Oracle System Identifier (SID) or Oracle service name.The type of information the DataDirect Connect for JDBC Oracle driver allows you to retrieve from a tnsnames.ora file includes: Retrieving Connection Information from a tnsnames.ora FileĭataDirect Connect for JDBC Oracle driver also supports retrieving specific connection information, including connection failover and client load balancing instructions, from a tnsnames.ora file. Typically, the application does not need to know which instance to which it is connected. The specific instance that is connected to is determined by a number of factors, including which instances are available and the load on those instances. Jdbc:datadirect: oracle://server1:1521:ServiceName=Accounting This document explains how you can take advantage of Oracle RAC features such as load balancing and connection failover using the DataDirect Connect for JDBC Oracle driver to connect your data critical applications to data. When connection failover occurs and a service connection is redirected to another node, users can continue to access the service, unaware that it is now provided from a different node. When a node failure occurs, connection attempts can fail over to other nodes in the cluster, which assume the work of the failed node. In addition, an Oracle RAC system can protect against computer failures caused by unexpected hardware failures and operating system or server crashes, as well as processing loss caused by planned maintenance. For example, in the event of a sudden increase in traffic, an Oracle RAC system can distribute the load over many nodes, a feature referred to as load balancing. A cluster architecture, such as Oracle RAC, provides applications access to more horsepower when needed, while allowing computing resources to be used for other applications when database resources are not as heavily required.
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