Using Serviceguard Extension for RAC, 6th Edition, April 2008

For example, on a two node cluster with one database, each node can have one RAC
instance and one listener package. Oracle clients can be configured to connect to either
package IP address (or corresponding hostname) using Oracle Net Services. When a
node failure occurs, existing client connection to the package IP address will be reset
after the listener package fails over and adds the package IP address. Subsequent
connections for clients configured with basic failover, clients would connect to the next
available listener package's IP address and listener.
Node Failure
RAC cluster configuration is designed so that in the event of a node failure, another
node with a separate instance of Oracle can continue processing transactions. Figure 1-3
shows a typical cluster with instances running on both nodes.
Figure 1-3 Before Node Failure
Figure 1-4 shows the condition where Node 1 has failed and Package 1 has been
transferred to Node 2. Oracle instance 1 is no longer operating, but it does not fail over
to Node 2. Package 1’s IP address was transferred to Node 2 along with the package.
Package 1 continues to be available and is now running on Node 2. Also note that Node
30 Introduction to Serviceguard Extension for RAC