How to ensure 3.5 inch Hard Drive a Smooth Installation? Check that your PowerEdge Server or Drive Array is listed and supported. Your Dell server has to have 3.5 inches Hot-Plug Drive Bay This 3.5 inch Drive caddy supports only 3.5-inch hard drives OR with 2.5 inch converter bracket also 2.5-inch hard drives. Please, contact us if you are not sure.