Your computer room will overheat next weekend

Dear readers in the United States,

I'm sorry. I have some bad news.  That tiny computer closet that has no cooling will overheat next weekend.

Remember that you aren't cooling a computer room, you are extracting the heat.  The equipment generates heat and you have to send it somewhere. If it stays there, the room gets hotter and hotter.

For the past few months you've been lucky.  That room benefited from the fact that the rest of the building was relatively chilly. The heat was drawn out to the rest of the building. During the winter, each weekend the heat was turned off (or down) and your uninsulated computer room leaked heat to the rest of the building. Now it's springtime, nearly summer.  The building A/C is on during the week. When it shuts down for the weekend the building is hot; hotter than your computer room.  The leaking that you were depending on is not going to happen.

Last weekend the temperature of your computer room got warm on Saturday and hot on Sunday. However, it was ok.

This weekend it will get hot on Saturday and very hot on Sunday. It will be ok.

However, next weekend is Memorial Day weekend. The building's cooling will be off for three days. Saturday will be hot. Sunday will very very hot.  Monday will be hot enough to kill a server or two.

If you have some cooling, Monday you'll discover that it isn't enough.  Or the cooling system will be overloaded and any weak, should-have-been-replaced, fan belts will finally snap.

How do we get into this situation?

Telecom closets don't have any cooling because they have no active components. It's just a room where wires connect to wires. That changed in the 1990s when phone systems changed. Now that telecom closet has a PBX, and an equipment rack.  If there is an equipment rack, why not put some PC servers into it? If there is one rack, why not another rack? By adding one machine at a time you never realize how overloaded the system has gotten.

Even if you have proper cooling, I bet you have more computers in that room than you did last year.

So what can you do now to prevent this problem?
  • Ask your facilities person to check the belts on your cooling system.
  • Set up monitoring so you'll be alerted if the room gets above 33 degrees C. (You probably don't have time to buy a environmental monitor, but chances are your router and certain servers have a temperature gauge on or near the hottest part of the equipment. It is most likely hotter than 33 degrees C during normal operation, but you can detect if it goes up relative to a baseline.)
  • Clean (remove dust from) the air vent screens, the fans, and any drives. That dust makes every mechanical component work harder. More stress == more likely to break.
  • Inventory the equipment in the room and shut off the unused equipment (I bet you find at least one server)
  • Inventory the equipment and rank by priority what you can power off if the temperature gets too high.
If you do have a system that overheats, remember that you can buy or rent temporary cooling systems very easily.

I don't generally make product endorsements, but at a previous company we had an overheating problem and it was cheaper and faster to buy a Sunpentown 9000 BTU unit at Walmart than to wait around for a rental. In fact, it was below my spending limit to purchase two and tell the CFO after the fact. I liked the fact that it self-evaporated the water that accumulated; I needed to exhaust hot air, not hot air and water.

Most importantly, be prepared. Have monitoring in place. Have a checklist of what to shut down in what order.

Good luck! Stay cool!

Tom

P.S. I wrote about this 2 years ago.

Posted by Tom Limoncelli in Technical Tips

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3 Comments | Leave a comment

Also remember to clean the screens, fans and drives of any dust which might have accumulated, which really holds the heat in, making it harder for the cooling equipment to work.

Another thing to do is actually have someone come in Sunday morning and turn the building A/C near the server room *on* for about 6 to 8 hours. Many building that shut off on the weekends have a timer that can turn it on for a while during non-programmed hours. Talk to your facilities people.

An ounce of prevention can save a week of grief.

Read this last night thinking that you're totally right and isn't something I've yet brought up to my customers - over here in the UK things aren't that bad yet, but with summer starting it's something that I'm going to move up my ToDo list.

The funny thing is today is quite hot and one of my 2 home ISPs is having problems in "many" of the exchanges they use. Terrifying, but something that's easily overlooked.

Thanks for the reminder!3

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