The figure shows clients, including Oracle Identity Management and middle tiers, using a virtual hostname or virtual IP to access two nodes (node 1 and node 2) in a hardware cluster. Node 1 is the active node, and node 2 is the standby node.
Node 1 and node 2 contain the following software on their local disks: Oracle home for the database, Oracle Fail Safe, and Microsoft Cluster Server.
Both nodes can access a shared storage which contains the data files for the database, but only one node (the active node) can mount the shared storage at any time.
Usually node 1 (the active node) runs the database processes. If node 1 fails, then a failover event occurs and node 2 becomes the active node, mounts the shared storage, and runs the database processes. The virtual hostname and IP also change to point to node 2.