I bought accommodate closet to my Drobo and a small UPS in the 19 inch the ground. Since in this type of soils the soil only the front side is mounted in the cabinet I just specially ordered me 25 cm deep.
Unfortunately, this exposure of the upper devices mentioned is not quite grown so that it is slightly slack. However, this is for me not a big problem. It keeps the load and does not look like he further bends.