If you are installing additional Oracle Database 11g products in an existing Oracle home, then stop all processes running in the Oracle home. You must complete this task because you cannot overwrite files that are used by the running processes.
Consider the following before you install Oracle Grid Infrastructure or Oracle Database:
• If you plan to use Oracle Restart, you must install the Oracle Grid Infrastructure before you install and create the database. When you perform a database installation, the database must use the same listener created during the Oracle Grid Infrastructure installation, thereafter you do not have to perform the steps listed in this section.
The default listener and any additional listeners must run from the Oracle Grid Infrastructure home.
• If you have an existing Oracle Database 11g Release 2 (11.2) running on Oracle Automatic Storage Management, then stop any existing Oracle ASM instance. After you finish installing the Oracle Grid Infrastructure software, start the Oracle ASM instance again.
If you choose to create a database during the installation, then most installation types configure and start a default Oracle Net listener using TCP/IP port1521 and the IPC key value EXTPROC. However, if an existing Oracle Net listener process is using the same port or key value, Oracle Universal Installer looks for the next available free port (for example, 1522) and configures and starts the new listener on this available free port.