A Day in the Life of a Datacenter, Part I
We’re going to take a look at a typical day in the life of a datacenter. We’ll start off with this post being about the environment – what it’s like inside. In later posts we’ll take you through some of the activities inside, from changing out hard drives, to racking Storage Pods, to diagnosing problems and more. Let’s get started.
Getting inside a datacenter
As one approaches a datacenter you’ll notice there isn’t much to notice. There’s no “here’s my datacenter” signage and the parking lot is nearly empty. You might wonder, “is this the right place?” While larger, more prominent, datacenters will have armed guards and gates, most datacenters have a call-box outside of a locked door. In either case, datacenters don’t like drop in visitors, so unless you’ve already made prior arrangements you’re going to be turned away. In short, regardless of whether it is a call-box or an armed guard, a primary line of defense is to know everyone whom you let in the door.
Once inside the building you’re still a long way from being in the actual datacenter. You’ll start by presenting the proper identification to the guard and fill out some paperwork. Depending on the facility and your level of access, you will have to provide a fingerprint that will be used for biometric access/exit confirmation. Eventually you’ll be given a badge or other form of visual identification that shows your level of access. For example, you could have free roam of the place (highly doubtful), or be allowed in certain defined areas (doubtful), or have to be escorted wherever you go (likely). For this post, we’ll give you access to the Backblaze areas in the datacenter, escorted of course.
We’re ready to go inside, so clip on your badge with your picture on it, get your finger ready to be scanned, and remember to smile for the cameras as you pass through the “box.” While not the only method, the “box” is a widely used security technique that allows one person at a time to pass through a room where they are video-taped and visually approved before they can leave the room. Speaking of being on camera, by this point you will have passed dozens of cameras – hidden, visible, behind one-way glass etc. – since you first stepped foot on the property.
Once past the “box” you’re in the datacenter, right? Probably not. Datacenters can be divided into areas or blocks each with different access codes and doors. Once out of the box, you still might only be able to access the snack room and the bathrooms. These “rooms” are always located outside of the actual datacenter floor. Let’s step inside the datacenter floor, “badge in please.”
Inside the datacenter
While every datacenter is different, there are three things that most people find common in their experience; how clean it is, the noise level and the temperature.
Datacenters are clean
From the moment you walk into a typical datacenter you’ll notice that it is clean. While most datacenters are not cleanrooms by definition, they do ensure the environment is suitable for the equipment housed there.
Cleanliness starts at the door where mats like the one above capture the dirt from the bottom of your shoes. These mats are replaced regularly. As you look around, you might notice that there are no trashcans on the datacenter floor. As a consequence the datacenter staff follows the “whatever you bring in, you bring out” philosophy. In addition, most datacenters won’t allow food or drink on the datacenter floor. Instead, you badge out of the datacenter floor to have a snack or use the restroom.
Besides being visually clean, the air in a datacenter is also amazingly clean as it is highly filtered to the sub-micron level. The filters used are typically rated with a 99.97% (or higher) efficiency in removing 0.3 micron particles. In comparison, your typical home filter provides a 70% sub-micron efficiency level. That might explain the dust bunnies behind your gaming tower.
Datacenters are Noisy
The decibel level in a given datacenter can vary greatly. As you can see above the Backblaze datacenter is between 76 and 78 decibels. This is the level when you are near the racks of Storage Pods. How loud is 78dB? Normal conversation is 60dB, a barking dog is 70dB, and a screaming child is only 80dB. In the US, OSHA has established 85dB as the lower threshold for potential noise damage. Still, 78dB is kind of loud so we insist that our datacenter staff wear ear protection on the datacenter floor. Their favorite earphones are the noise reduction type by Bose, they are a bit costly, but well worth it.
The noise comes from a combination of the systems needed to operate the datacenter; air filtration, heating and air conditioning, electric, etc. combined the sound of about 6,000 spinning 3-inch fans in the Storage Pods.
Datacenters are hot, datacenters are cold
As noted, part of the noise comes from heating and air-conditioning systems, mostly air-conditioning. As you walk through the racks and racks of equipment in many datacenters, you’ll alternate between warm aisles and cold aisles. In a typical raised floor datacenter, cold air rises from vents in the floor in front of each rack. Fans inside the servers in the racks, in our case Storage Pods, pull the air in from the cold aisle and through the server. By the time the air reaches the other side, the warm aisle, it is warmer and is sucked away by vents in the ceiling or above the racks.
There was a time when datacenters were like meat lockers with some kept as cold as 55°F (12.8°C). Warmer heads prevailed and over the years the average temperature has risen to over 80°F (26.7°C) with some companies pushing that even higher. That works for us, but in our case we are more interested in the temperature inside our Storage Pods and more precisely the hard drives within. Previously we looked at the correlation between hard drive temperature and failure rate. The conclusion: As long as you run drives well within their allowed range of operating temperatures, there is no problem operating a datacenter at 80°F (26.7°C) or even higher. As for the employees, if they get hot they can always work in the cold aisle for a while and vice-versa.
Getting out of a datacenter
When your datacenter visit is done, remember to leave yourself a few extra minutes to get out. The first challenge is to find your way back to the entrance. If you are escorted, there’s no issue, but if you’re on your own I hope you paid attention on the way in. It’s amazing how all the walls and doors look alike as you’re wandering around looking for the exit, and with datacenters getting larger and larger the task won’t get any easier. For example, when completed in 2016, the Switch SUPERNAP datacenter complex in Reno Nevada will be over 6.4 million square feet, roughly the size of the Pentagon. Having worked in the Pentagon, I can say that finding your way around a facility that large can be daunting. Of course, a friendly security guard is likely to show up to help if you get lost or curious.
On your way back out you’ll pass through the “box” once again for your exit cameo. Also, if you are trying to leave with more than you came in with you will need a fair bit of paperwork before you can turn in your credentials and exit the building. Don’t forget to wave at the cameras in the parking lot.
Join us on our next datacenter visit as we follow around our datacenter techs to see what a day in datacenter is like for them
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