A single node RAC install means that CRS is installed, and db and other services run under the control of CRS, and you have the option of adding another node at a later date without having to reinstall the software (i.e. converting from a non-RAC to a RAC install). Sometimes we get requests to create a single node RAC for testing- it is more to simplify the DBA's work during a later conversion to RAC, or to validate the OS platform for RAC without having to get a 2nd node. From: Bradd Piontek [mailto:piontekdd@xxxxxxxxx] Sent: Tuesday, March 09, 2010 5:56 PM To: bill@xxxxxxxxxxxx Cc: Crisler, Jon; oracle-l@xxxxxxxxxxxxx Subject: Re: Oracle RAC licensing question I really don't like getting into licensing questions ... however What is a single-node RAC installation? I believe all Enterprise Edition gets you is the ability to use the Clusterware (Grid Infrastructure), not install the RAC option in the database. http://www.oracle.com/database/product_editions.html Bradd Piontek Pythian - Love Your Data On Tue, Mar 9, 2010 at 4:45 PM, Bill Zakrzewski <bill@xxxxxxxxxxxx> wrote: Jon - You probably have to verify with your customer support rep, but I believe even a single-node RAC installation requires a the RAC license. All licensing questions usually favor Oracle. -Bill On Mar 9, 2010, at 5:05 PM, Crisler, Jon wrote: If I run a single-node RAC cluster, do I actually need to purchase a RAC license, or will a Oracle Enterprise license be sufficient ?