Air enters through the two
front 80mm fans.
Blows over the sides and over the two harddisk clusters.
Then leaves the cabinet via two 80mm fans (one in the PSU).
A thing to
note is the air that goes over the drives also cools the bottom of the
server above it.
The heat from the drives is dissipated in the aluminum cover on the top
To further keep the temperature and power usage down all the
hard drives spin down after 10 min of inactivity.