I followed your 11gr2 RAC on OEL5 using Virtualbox (http://www.oracle-base.com/articles/11g ... ualbox.php) article. Is it correct that after the installation, only 1 SCAN ip will be enabled (hence, only 1 SCAN Listener will be active too)? Is this because we are using hosts file instead of DNS?
If you are installing 220.127.116.11 and using the hosts file, then only 1 SCAN listener will be started.
If you are using 18.104.22.168, you need to use DNS. If you use DNS, then you will have as many SCAN listeners as addresses the DNS resolves to. If the DNS resolved to 3 round-robin addresses, then you will have 3 scan listeners.