Combine all the ingredients for the dry rub in a bowl.
Rub down your pork shoulder with the dry rub. Use all of the rub.
Store the pork shoulder, covered, in your fridge for 24 hours or longer.
Smoke the pork in your smoker at 220f for 4-5 hours up to an internal temperature of 200f degrees.
Once you get to an internal temperature of 200f, wrap it in foil and move it into an oven at 210f for another 4-5 hours. This step will tenderize the pork without letting it turn into mush. You could continue to use your smoker for this, but the oven has better temperature management and will reduce the risk of your BBQ drying out.