Sometime I had doubt that why we could not use the same RCU for multiple OBIEE installation. So here is the answer:
If your organization has an MDS schema installed in a supported database, you do not need to CREATE the MDS schema again with the RCU. You can use the existing MDS schema for your Oracle Business Intelligence installation. For this option, deselect the Metadata Services schema in the Select Components screen of the RCU. Then, when you install Oracle Business Intelligence, specify the details for the existing MDS schema in the MDS Schema screen.
However, each Oracle Business Intelligence system (BI domain) requires its own BIPLATFORM schema. Two or more systems cannot share the same BIPLATFORM schema, although they can share the same database. Therefore, you must run the RCU and install the BIPLATFORM schema and the MDS schema (if no MDS schema exists) before installing each distinct Oracle Business Intelligence system (BI domain). For example, if you plan to install two Oracle Business Intelligence systems, you must run the RCU and install the required schemas twice, or once for each system.
This requirement does not apply when you scale out an Oracle Business Intelligence system. In a scaled-out (clustered) system, you only run the RCU and install the database schemas once, before installing the primary node of the Oracle Business Intelligence cluster (the BI domain for the cluster is created at that time). Additional Oracle Business Intelligence nodes that you install during the scale-out process become members of that domain and, therefore, use the same set of schemas.
1. If we are installing OBIEE 11g system in multiple machine in same LAN We can use Same
MDS schema which we have created with RCU Installation.
2. We have to create BIPLATFORM schema for each OBIEE 11g installation alone. So we need
to run RCU to create BIPLATFORM schema.
3. Scale-out of OBIEE 11g system will not fall in the line. One RCU with one primary node will
be installed and another Node will install only BI component in another machine.