Where did you find out that you should be playing from the internal drive??
whilst it does have disadvantages (what if someone unplugs it halfway through your set?) there is nothing inherently wrong with it..
Just make sure that you always have the drive plugged into the same USB port before you open Traktor.. 🙂
On the subject of backups, you should always have them. A copy with you, a copy back at home and a copy in a different building somewhere (at a relative’s?). Then keep them updated.
I use a program called All-Way sync to make my backups. It compares 2 drives and then only transfers the data which has changed (it scans date modified as well as checking for new files) which means that it takes a lot less time than just copying the whole set of data again and again each week.. And it can run automatically 🙂
bob6397