System configuration figures are shown below:
In scalable operation with RAC, Oracle is operated on all nodes. A client can use a database that is connected to either node.
In standby operation, a cluster system consists of an operational node and standby nodes. On the operational node, Oracle applications, a logical IP address and shared disks are active. On the standby nodes, these resources are inactive. In the event of a failure, production operation is switched to one of the standby nodes, and the resources in this standby node are activated. The client can connect to the running node using the logical IP address without configuration changes.