You're welcome.
Given your current experience, I assume you're rather
DBA oriented and not so interested in learning development.
To be honest, I believe that if you want to gain some knowledge in
Oracle Database, you should start with the basic administration: see
2 day DBA, for example.
Than you should read and study the
Concepts and the
Administrator's guides. It would be great if you buy and read some good non-free
Oracle book,
in my opinion,
Tom Kyte's books are a must for every
DBA and developer.
And yes, as I already said, I would suggest to go for
RAC only after you gained some real world good working knowledge of the
Oracle database.
Unfortunately, as far as the
Oracle database is concerned, there are no "
shortcuts" in the learning path.