It’s 3:00 in the morning and you can’t sleep. The natural response is to bust out your phone and waste some time on Reddit, get to swiping on Tinder or blow a few more dollars on that freemium Game that’s quickly becoming a real problem. And luckily for you, these services work without a hitch. Because they’re all being provided to you from huge data centers that are expected to be reliable. No matter how many people are connected or what time of day it is.
But how do they stay running with almost no downtime? Well, it starts with having facilities and computers that are purpose-built to handle lots of incoming connections.
Although some services have their own data centers, many others who either don’t need or can’t afford a dedicated facility or need additional capacity, actually rent server space and processing time from larger companies.
A strategy called Co-location. They typically make data centers up of lots of servers sitting in racks, to maximize how many machines can fit into one bit of floor space. But setting up a data center is a lot more complicated than just throwing a bunch of servers into a warehouse and calling it a day.
Larger data centers hold so much equipment, that they are actually built to be sturdier than your average building to accommodate all the extra weight from these large racks of servers. Some of them are so large that the workers inside are even given small vehicles like scooters or bicycles, so they can get around and troubleshoot issues more quickly.
Also, those servers generate a ton of heat. So elaborate cooling systems, including water chilling, are often employed. Additionally, data centers are often laid out to be more efficient. For example, servers will usually either face toward each other or directly away from each other to create what are called corridors of hot air that can be pushed out more easily.
But, when there’s an environmental hazard that isn’t considered, huge problems can result. For example, a few years ago, Facebook actually had weather in the form of clouds inside one of its data centers, which caused some equipment to short out.
So humidity control can also be very important for larger operations. Some servers are even designed to withstand even more serious hazards like earthquakes, using braces and extra floor mounting.
Data centers are protected with advanced physical and human security, but what about the more technical challenges? Well, aside from encrypting it, data is often kept safe by spreading the processing and storage across multiple locations, rather than having them just on one machine in one place.
To make this simpler, servers are very often virtualized. Meaning that one physical server can be seen as several systems. This is incredibly useful because it allows a much greater number of tasks to be performed by one server. And that’s really important for Co-location, so as long as each virtual machine is separated well enough from the others, this can even bolster security.
Load Balancing is another technique that ensures that servers are being used efficiently. I mean, you don’t want a situation where some servers are getting slammed with requests and extra processing, while others are sitting idle. Like that kid who contributed nothing to your group projects back in school. Instead, servers are often configured to have their workload and their data balanced more evenly between them. This prevents overloading of certain machines and bottlenecks.
This is also often done automatically in cases where one server might need to be taken down for maintenance. So that whatever it was working on can just be picked up by other servers.
In a similar vein, Redundancy is a critical feature of any modern data center. Copies of data are usually kept on multiple servers or even across multiple data centers. These facilities often have multiple pipelines leading out to the public Internet. In case one Internet Service Provider has a problem.
So all this means that enterprise-grade data centers are designed for at least 99.999 percent uptime. Which works out to about five minutes of time offline per year.
Some of them are actually even more reliable than that. While websites and online services do obviously go down sometimes. It really is amazing how much has gone into making sure that we can access nearly anything, nearly any time.