Once the Oracle binaries are obtained the administrator is ready to begin the installation process. The first step is to read the supplied installation guide and to ensure that all prerequisites are met. OER can be installed in 32 or 64 bit environments but generally, we would recommend 64-bit since 32-bit architecture is limited to addressing less than 4 GB of RAM. With a 64-bit architecture, all system memory can be addressed and there are therefore more options available for JVM tuning.
Oracle provides a OER sizing guide that can be used as a guide for sizing environments and is located at the following URL: http://www.oracle.com/technetwork/middleware/repository/overview/oer11gsizingguidelines-130307.pdf