How are you reading this article? Are you sitting at your computer? Laptop? Tablet? As you read do you ever stop to think where everything is being stored? On a USB card? In some “server room” somewhere? On-site? Off-site? What, exactly, is “The Cloud”?
Cloud Computing – or often more colloquially “The Cloud” is the name coined for modern information systems where most of the information storage and processing occurs in remote locations. Your computer, laptop, tablet or even phone only needs to be able to connect to the system and display an interface.
A Data Center is a location where computing services are centralised – often to provide cloud computing facilities. Think of a large room full of flat boxes mounted into racks. Acres and acres of them. Each one of those boxes is a powerful computer server and coupled together they provide data services to people like you, reading this article.
Now in the time it takes you to navigate to this article and start reading it your computer will have warmed up. If you are using a laptop you might notice that your legs are a bit warmer now than they were earlier. A traditional desktop computer will probably be blowing out warm air by now – you can feel it if you put your hand near the vents.
If that’s how warm a single computer can get, doing a fairly simple task of displaying a fairly simple article just imagine how hot a rack of twenty or so computers could get. And each corridor in a data center has tens, if not hundreds of racks of computers all working hard serving websites and running web apps in the cloud. To give you an idea of how big these places can be, Google opened a data center in 2016 which covers 352,000 square feet. And that is just one of the locations that they operate from.
Hot Hot Hot!
As you can imagine data centers can get very hot, very quickly, unless large scale cooling systems are built into the structure. Fans can blow warm air away from delicate internal components but that simply pushes the heat elsewhere. Unless the entire room is air-conditioned and cooled moving the air around will do very little to protect the processors. In a best case scenario, they will simply shutdown and refuse to switch on again until the temperature has fallen. In a worst case, thousands of pounds’ worth of computer equipment – and possibly even more disastrously – the data stored on them – could become broken, corrupted and fit only for scrap.
Why Do They Get Hot Anyway?
To understand where all the heat is coming from we need to understand about what happens when you pass an electric current through a wire. Think of an incandescent light bulb – the sort with a wire in the middle. When electricity passes through the wire the wire glows which produces light. It also produces heat – the old-style tungsten light bulbs wasted a lot of energy as heat. You could feel it when you went to change a broken one.
Inside computers are, essentially, millions of tiny wires. They’re embedded into the silicon chips but the same effect applies. As the electric signals are pushed along the wires some of the electrical energy is wasted as heat. For each signal, it might be only a tiny amount – but every second millions of signals are being passed around the insides of the computers and all those tiny bits of heat loss multiply up into a huge warming of the chip.
In order to prevent the chips themselves from simply melting under the heat produced the chips are fitted with heat sinks and coolers. These transfer the heat away from the chip. Fans in the casing of the computer then blow the hot air out of the case and into the surroundings.
Remember what we said about each computer being mounted in a rack of other computers? Each computer is also blowing hot air out into the room. If the hot air in the room isn’t replaced by cool air then, eventually, the whole room will overheat which will not only damage a lot of expensive computer equipment but could also make it dangerously hot so that service personnel are unable to access the systems to maintain them.
So, having a good air-conditioning system in your server room or data center is essential to keep your computer systems running. Luckily, most computers these days have over-heat prevention to shut them down if they reach the top of their operating temperature range. Which means that at least your data shouldn’t be damaged.
Ensuring that your data center is adequately air-conditioned is, arguably, more important that ensuring that your offices are. Your staff can move to a cooler location but your computers are stuck where they are installed – however hot it gets.
Keeping an Eye on Things
Data center cooling can be hugely energy intensive and the amount of cooling required can vary considerably depending on the workload of the systems. Overnight, when they are basically just running routine updates and backups can generate less heat than when everyone is trying to use the system during the day.
Central to running a data center efficiently is temperature control. By fitting a series of temperature sensors around the room cooling can be targeted to the places that are generating the most heat. Instead of trying to bring the entire space down to a comfortable temperature individual fans can be switched on or off or boosted to increase the amount of air movement when it is needed.
Data Center cooling is a complex subject that requires professional advice – ideally at the design stage. Depending on the type and number of systems in the data center different cooling strategies will be needed. Ultimately though keeping it cool means knowing how hot it is getting.