I want to get my recordings off my main computer HD. I'm looking at a 4tb drive.  (I have 3 cameras. My plan is to have 8-10 cameras when I'm done). Anyway, I'm trying to decide if a second internal 4tb HD is better than say a WD MyBook 4tb NAS. Hard drives are cheap. But I like the ability to literally hide my recordings anywhere I can run a cat5 and power. And then there is the USB hard drive.  Fairly cheap but with the planned 8-10 cameras I'm afraid I may over load the connection. 
Btw I'm currently doing motion w/ Dahua HDW4300C and 2 HDW4421C. 15fps
Thoughts?
 Btw I'm currently doing motion w/ Dahua HDW4300C and 2 HDW4421C. 15fps
Thoughts?