Hi John, I assume you're talking JDBC thin client, since w/ thick, you just use a load-balancing/failover connect string. I also assume you're using a JDBC thin URL that looks something like this: jdbc:oracle:thin:@rac01:1521/pqprd So, the above will connect to rac01 node every time, and will not help w/ load balancing and failover. If rac01 crashes, my app is dead in the water. However, you can do something like this w/ JDBC: Jdbc:oracle:thin@ (DESCRIPTION =(LOAD_BALANCE=on)(FAILOVER=on) (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = rac01-vip)(PORT = 1521)) (ADDRESS = (PROTOCOL = TCP)(HOST = rac02-vip)(PORT = 1521)) (ADDRESS = (PROTOCOL = TCP)(HOST = rac03-vip)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = pqprd)(FAILOVER_MODE=(TYPE=SELECT)(METHOD=BASIC)))) In other words, you can embed the entire load balancing, failover enabled connect string into your JDBC thin url. Hope that helps, -Mark -- Mark J. Bobak Senior Database Administrator, System & Product Technologies ProQuest 789 E. Eisenhower, Parkway, P.O. Box 1346 Ann Arbor MI 48106-1346 +1.734.997.4059 or +1.800.521.0600 x 4059 mark.bobak@xxxxxxxxxxxx<mailto:mark.bobak@xxxxxxxxxxxxxxx> www.proquest.com<http://www.proquest.com> www.csa.com<http://www.csa.com> ProQuest...Start here. From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of John Dunn Sent: Thursday, August 14, 2008 5:32 AM To: oracle-l Subject: RAC failover and JDBC string I need to understand how RAC handles hostnames in JDBC connection strings. If I have an application that uses a JDBC connection string(that contains a hostname) to connect to the Oracle database, what happens if there is a failover to another server in the RAC cluster?