Always provide adequate space in front of and behind the rack to allow for proper ventilation of the rackmounted controllers. Do not obstruct the front or rear of the rack with equipment or objects that might prevent air from flowing through the rack. Rackmountable controllers and equipment, including the Oracle ZFS Storage ZS5-ES, typically draw cool air in through the front of the rack and let warm air out the rear of the rack. There is no airflow requirement for the left and right sides due to front-to-back cooling.
If the rack is not completely filled with components, then cover the empty sections will filler panels. Gaps between components can adversely affect airflow and cooling within the rack.