The figure shows nodes on two tiers. Each tier has its own virtual hostname and IP address.

• In one tier, you also have an active node (node 1) and a passive node (node 2). The active node runs OracleAS Metadata Repository, Oracle Internet Directory, and Oracle Directory Integration and Provisioning. This node has access to the shared disk, where these components are installed. The oraInventory directory is also on the shared disk.

  If node 1 fails, node 2 becomes the active node in this tier. It gets access to the shared disk, becomes associated with the virtual hostname and IP address, and runs the OracleAS Metadata Repository, Oracle Internet Directory, and Oracle Directory Integration and Provisioning components.

• In the other tier, you have an active node (node 3) and a passive node (node 4). The active node runs Oracle Delegated Administration Services and OracleAS Single Sign-On. This node has access to the shared disk, where Oracle Delegated Administration Services and OracleAS Single Sign-On are installed. The shared disk also contain the inventory directory. The virtual hostname and IP address are associated with the active node.

  The passive node, node 4, becomes active if node 3 fails. It gets access to the shared disk, becomes associated with the virtual hostname and IP address, and runs the Oracle Delegated Administration Services and OracleAS Single Sign-On components