Bikepacking on a New Rockhopper
Bikepacking tends to be more lightweight and generally doesn't involve panniers or racks. Just look at the rigs used by tour divide riders (http://bikepacker.com/2016-tour-divide-rigs/). If you think you need pannniers, then perhaps you are talking about touring rather than bikepacking.

Bikepacking luggage will typically require one or more of the following:


handlebar harness
seatpost pack
framebag


This sort of setup is especially useful for off road/trail riding as weight is kept to a minimum and storing your heaviest items stored at the bottom of your frame bag will keep your centre of gravity low and improve handling. Something not so important in touring