After searching a little bit, I wasn't able to find any specific information on this, so here I am. We've got a single 42U rack with 6 servers and some switches. It is currently housed in a coat closet with a 14,000 btu portable air conditioner (our third!). We need to move our servers into a properly configured space. One idea that has popped up is a custom built walk-in cooler. At first, I thought this might be a great idea, but then I thought about ventilation, humidity, and electrical concerns. Does anybody have any thoughts on this idea? I'm guessing that there are some really obvious reasons (that I'm missing) why this is not a good idea…
Walk-In Cooler Server Room
physical-environmentserver-room
Related Solutions
Recommendations on server room temperature vary greatly.
This guide says that:
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.
This discussion on Slashdot has a variety of answers but most of them within the range quoted above.
Update: As others have commented below Google recommends 26.7°C (80°F) for data centres.
Also the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) has recently updated their recommended tempature range to be from 18°C-27°C (64.4°F-80.6°F).
However this article agains highlights that there is still no consensus on the subject. As mentioned in the article I would highlight that:
...nudging the thermostat higher may also leave less time to recover from a cooling failure, and is only appropriate for companies with a strong understanding of the cooling conditions in their facility.
IMO most companies would not have such a strong understanding of cooling conditions and thus it would be safer in a small business environment to be running the rooms a little cooler.
NB: It is important to note there are a lot more factors to consider in a server/data room than just the temperature, air flow & humidity for example are also important concerns.
You're on the right track in terms of ventilating the hot air to the outside. You need to cycle fresh cool air in to the room\cabinet and exhaust the hot air out of the room\cabinet. You do not want to recycle the same air around and around. The key is to maintain airflow through the room: bring fresh, cool air in and send hot air out. My opinion would be to use the exhaust duct in the attic to send the hot air to the outside rather then sending it into the attic. If you have adequate airflow you may not need a portable air conditioner. Try it for a few days\weeks with just exhausting the hot air out of the room and see how that works. If it's still too hot for your comfort level (from the server's perspective) then go ahead and invest in a portable air conditioner. Be wary if the air conditioner has a water collection tank that you'll have to manage the emptying of it unless you can hook up a drain hose to it and sent it down the storm drain\sewer.
Best Answer
The idea was actually used for server rooms at one point in time. Today we understand that in-rack (small deployments), hot/cold isles, raise floor ventilation, and the 'newest' open-circulation designs are more efficient and have a considerably better ROI than putting your DC in a commercial size refrigerator.