http://zakkiahmed.wordpress.com/2010/08/04/convert-11gr2-non-rac-database-to-rac-database-using-rconfig/
http://docs.oracle.com/cd/B28359_01/install.111/b28264/cvrt2rac.htm
http://docs.oracle.com/html/B14406_01/cvrt2rac.htm