I got the DVD I wanted... Now I want to make a copy for safekeeping, in case it kills itself on accident someday. I use a Macintosh... What do I do?

This DVD (Transformers 2) is AWESOME! I just wanna keep it for safekeeping forever… What happens if it breaks down one day? So I’ve tried Mac the Ripper for my Mac, and I’ve also tried Handbrake. The DVD has 7 GB total, and I want to burn it too… Can you help me either keep the scene selections and make the DVD file smaller (SL DVD 4.66 GB) or anything else?