When should I jump on HBase rather than RDBMS?

Hello everyone,

I read through some literature and end up with some ideas on HBase and RDBMS. Please correct me if I am wrong:

* Use HBase if the application is going to handle large datasets, like Petabytes. That means when scalability is a big concern; Also, because HDFS replicates data autoamtically, we have reliability;

* Correspondingly, we can just use RDBMS when the dataset is not huge enough to worry about scalability often. Because anyway, RDBMS has more functionalities we can take advantage of, e.g. secondary indexing, referential integrity.

Is the above right?

Regards,
Elton