And two ounces dry, depending on the shape of the pasta, is about one half cup cooked.
So if you were going by the servings a nutritional would use - 8 ounces of dry pasta would be about 4, half-cup servings of pasta.
But people usually eat more than the half cup, so if you are trying to figure this out for a dinner plan and not a nutritional plan - I would count on at least one cup (or 4 ounces dry) per person, and possibly more if that is the main course.