Why use RAC?

Oracle RAC lets you cluster two or more servers and present a single database to your applications across all nodes within the cluster.  The benefits of this vary according to the needs of differing organisations.

For some, the benefits are delivered simply by having two servers in place, giving both scale and a really easy method of dealing with the scenario where one box experiences an outage.  In smaller environments, this is achieved using Oracle Standard Edition, so there is no extra licence cost for using RAC.

For larger organisations, RAC offers an easy method of incrementally scaling infrastructure as requirements and budgets grow.  Large organisations with existing large volume requirements can use RAC technology as a component of building a grid infrastructure to flexibly support the delivery of server and database resources to a variety of business applications.  Today, this approach has been adopted to enable “private cloud” style delivery, where utility computing thinking is applied to provide resources to departments as a service, with internal cost centre apportioning based on usage.  This places lower demands on department budgets and delivers them more robust infrastructure for a lower cost than equivalent silos.  It also provides IT with a much easier to manage environment and one which can flexibly respond to changes in business requirements.