Every store is different. The store I work for was designed for Starbucks at least 20+ years ago. Our back room is very small. We try to use every inch of our walls for shelving. We have shelving above every door frame to store our less used items such as sugar boxes and silverware boxes.
We also have shelving in our 3x4 mop room starting at the ceiling. We store non food items under the shelving units in baskets such as paper towels and toilet paper so we can move them around when we do back floors. We have rolling storage carts under the dish pit that store the dish pit chemicals sponges etc. because our BOH is so small we also have a cabinet that we have named “Narnia” in the FOH that we store our syrups, oven supplies, berries and RTDE backstock like juice & H2O.