One of the most efficient ways to become familiar with Oracle Real Application Clusters (RAC) 11g technology is to have access to an actual Oracle RAC 11g cluster. There's no better way to understand its benefitsincluding fault tolerance, security, load balancing, and scalabilitythan to experience them directly.
Unfortunately, for many shops, the price of the hardware required for a typical production RAC configuration makes this goal impossible. A small two-node cluster can cost from US$10,000 to well over US$20,000. That cost would not even include the heart of a production RAC environmenttypically a storage area networkwhich can start at US$10,000.
The article continues at http://www.oracle.com/technology/pub/articles/hunter_rac11gr1_iscsi.html?rssid=rss_otn_articles