VirtualBox 하드디스크 확장

링크1: http://mc500.tistory.com/entry/VirtualBox-%ED%8C%8C%ED%8B%B0%EC%85%98-%ED%99%95%EC%9E%A5-%ED%95%98%EA%B8%B0

링크2: http://www.my-guides.net/en/content/view/122/26/