This figure shows an Oracle WebCenter two node high availability architecture. The load balancer in the web tier routes requests to the Oracle HTTP Server instances on WEBHOST1 and WEBHOST2. The application tier hosts are APPHOST1 and APPHOST2. These hosts include five separate clusters: the Spaces Cluster, which is comprised of the WC_SPACES1 managed server on APPHOST1 and the WC_SPACES2 managed server on APPHOST2; the Portlet Cluster, which is comprised of the WC_PORTLET1 managed server on APPHOST1 and the WC_PORTLET2 managed server on APPHOST2; the Collaboration Cluster, which is comprised of the WC_COLLABORATION1 managed server on APPHOST1 and the WC_COLLABORATION2 managed server on APPHOST2; the Utilities Cluster, which is comprised of the WC_UTILITIES1 managed server on APPHOST1 and the WC_UTILITIES2 managed server on APPHOST2; and the Custom App cluster, which is comprised of the WC_CUSTOM_APP1 managed server on APPHOST1 and the WC_CUSTOM_APP2 managed server on APPHOST2. The active Administration Server is on APPHOST1, and the passive Administration Server is on APPHOST2. The data tier includes an Oracle RAC database .