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 and bottom.

To further keep the temperature and power usage down all the hard drives spin down after 10 min of inactivity.

Ive been using HDD Thermometer for a couple of months but it will only log the temp of the drives from the onboard IDE channels so Im still looking for a better temp logger.

Id like to thank Lauritz J. Saxtrup he made a program to plot the temperature reading from HDD Thermometer

The temperature rise occurred when I moved the servers to the new rack resulting in the hot air from the living room being used for cooling.

If you know a utility that can log the HD temps and plot them on a graph please send me an email.