Whs 2011+Flexraid+Hp N36L

Guys I have a question.

I am plannign to install WHS 2011 on this with FlexRaid.
I currently have a single 3tb Seagate drive (I plan to add more drives later and have a 1 drive parity).

Here is my question, What happens to the OS partition? Does that get included in the FlexRaid parity?

Basically I want to be able to restore the ENTIRE hard drive if it fails which Flexraid would allow me to do if one drive fails and I have 1 drive set for parity.

HOWEVER, what if the drive that fails is the drive that has the OS on it?

How will I got recovering that drive?

Thanks guys