Managing data centers requires a focus on the type and capability of hardware, the appropriately robust software, and the space in which to put the entire system. The customer is usually more concerned with security and performance and the temperature of the system is rarely mentioned. But data centers only function if careful consideration is given to the alignment of servers and careful temperature control within server rooms. Even the most modern technology requires a bit of air conditioning in order to stay cool enough to work well.
Cool Air In, Hot Air Out
Every server functions the same way; cool air is sucked in the front and the heated air is blown out the back. This intake and exhaust system is fairly efficient as long as there is cool air in the room and space around the servers for air to circulate.
An Orientation Problem
One logical way to orient servers is to line them up all facing in the same direction, like students in a classroom. Unfortunately, this causes a temperature problem that is extremely inefficient and leads to malfunction of the servers due to overheating.
Each row of racks will blow hot air toward the row behind. That hot air will be sucked into the intake of the row, and it will be further heated and blown toward the intake of the next row. The result is that as the air moves through the room it gets hotter and hotter, until the back rows are overheating. Cool air is never able to get to the front of rear rows in this kind of orientation.
Hot and Cold Aisle Containment
Hot and cold aisle containment is the opposite orientation. Servers face one another both front to front and back to back, alternating each row. This means that cool air is being sucked in on both sides of one aisle and hot air is flowing out on both sides of the next aisle. The result is that air flow moves in a way that keeps hot air from being sucked in by intake fans.
To complete the picture, venting from the room must be aligned with the ‘hot’ aisles where the backs of two rows of racks face one another. Cool air must still be piped into the server room, but the data center becomes much more efficient and effective at staying at a reasonable and safe temperature.