8hrs in to render and still there are white patches all over my image.How much time does it take to finish render
Everything from 2 hours to 2 weeks, depends on your lights, materials, image size ....
I highly recommend you go over to the Reality Thread and post you issues there - http://www.daz3d.com/forums/discussion/289/ - All the Reality users will be more then willing to help you narrow it down.
I also suggest you post a current copy of your image if possable so we can see what your seeing. I would like to help as well as a Reality/LuxRender user but without some info on your image and the settings used in Reality its impossible to give proper feed back. So please hop on over there and let us know some more about the issue and we will give you a hand.
ps, please remember that LuxRender NEVER stops rendering. It is up to you to decide when it looks good and you can stop it when it does! And restart it again later if you want.
Some things that slow down Luxrender renders are lots of glossy materials and 'open' spaces with certain types of lights. Also the type of rendering, size of the image play a big part, too.