BIG DATA and Mission Critical DB's

Hi all,
I am wondering about this term "big data" and have been researching for a few weeks' now. I'm curious if the trend in the industry if to have mission critical back end db's have this big data and if MS SQLSERVER is a good choice for that end. What I'm talking about is terabyte sized data, real time, and having that data live for architects, analysts and what have you.

Be advised, I'm a newby DB and would consider myself a novice, but I do know a little bit about "small data" db's and using them for 1-off projects.

Any thoughts, ideas?

We have tb size oltp db on sql server and works fine so far.