HP Serviceguard Extension for RAC (SGeRAC) manual Before Node Failure

configured to automatically fail over from the original node to an adoptive node. When the original node is restored, the listener package automatically fails back to the original node.

In the listener package ASCII configuration file, the FAILBACK_POLICY is set to AUTOMATIC. The SUBNET is a set of monitored subnets. The package can be set to automatically startup with the AUTO_RUN setting.

Each RAC instance can be configured to be registered with listeners that are assigned to handle client connections. The listener package script is configured to add the package IP address and start the listener on the node.

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. For 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 3 shows a typical cluster with instances running on both nodes.

Figure 3 Before Node Failure

Figure 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. The IP address for package 1 was transferred to node 2 along with the package. Package 1 continues to be available and is now running on node 2. Also, node 2 can now access both the Package 1 disk and Package 2 disk. Oracle instance 2 now handles all database access, since instance 1 has gone down.

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