What temperature is right?
General recommendations suggest that you should not go below 10°C (50°F) or above 28°C (82°F). Although this seems a wide range these are the extremes and it is far more common to keep the ambient temperature around 20-21°C (68-71°F). For a variety of reasons this can sometimes be a tall order.
How do you maintain the right temperature?
Purpose built server rooms are well insulated for fire precaution reasons and air conditioning is essential. In many companies however the maintenance of the air conditioning is separate from the running of the servers. If the air conditioning fails you might not be the first to know. You may even be the last.