Use Solid Wall Cabinets

Cabinets used to have holes in the tops and bottoms, and quite often the sides were removed when installing multiple cabinets. That meant that an entire row of cabinets may not have any inside walls, except for the two ends. As you add more servers to the cabinet, the air simply finds the path of least resistance to the top of the cabinet. What path was that? Right through the path you created between the cabinets – the cooled air would just pass up the servers, leaving them much too hot. With today’s front-to-back-cooled server, the cabinets are designed to force the air to go in through the front and pass through the servers too. These racks minimize the number of holes in the top and bottom, and have solid, non-removable walls on all sides. This ensures that the airflow through the cabinet and servers is evenly distributed and consistent.

Install an Equal Number of Servers in All Cabinets

As we all know, the more hardware there is in a cabinet, the more heat will be generated. If you note which cabinets are full, you’ll probably also notice that they generate more heat and are usually clustered together. By doing this, you’ll be forcing a single cooling system (air conditioner) to work much harder than the rest. It may still work, but you need to keep in mind that air conditioners work most efficiently when they can work together to standardize the power supplied to each cabinet. If you can evenly load each cabinet, you’ll be able to evenly distribute the load between air conditioners, which will result in much lower cooling costs. What do we recommend? Limit the maximum peak load per rack to about 8.5 kW, and the average working load to 5.4 kW.

Use Wire Mesh to Hold Network Cabling

As we’ve mentioned in a past post, network cables almost always used to run in troughs beneath the floor. There had to be large holes in the troughs and in the floor tiles so that the cables could go from the floor to the cabinets. But now it’s recommended that you install simple wire mesh raceways (cable trays) and hang them above the cabinets. You’ll be able to have as few or as many cables in there as needed by your cabinets. What’s the advantage? The head will just go through the wire mesh instead of around it. However, you’ll want to remember to install and HANG the wire mesh tray at least four inches above the cabinet so that you can move or remove the cabinet without having to mess with the wire mesh.

Run Your Cables on Top of the Cabinets

We’ve all lived in the past, and perhaps still are, when the network cables were run below the floor and into the bottom of the cabinet. However, this system significantly restricts the under-floor airflow where there is a lot of cabling. In consequence, an uneven amount of air would be released into each cabinet. We all know that network cabling runs and cabling changes occur much more frequently than we’d like, and definitely more often than power cabling, so it only makes sense that we run the network cables over the cabinets instead of underneath. This will make it easier to access, drop, run, pull, and trace cables when changes need to be made. And as was mentioned, you’ll also create a much more even distribution of the cool air throughout the server room. That means your air conditioner will need to run less, saving your organization money

Implement Perforated Raised Floor Panels in Cold Rows

It used to be that you’d place perforated raised access panels below the servers’ cabinet to force the air into the cabinet, which would cool the lower servers fine, but what about the top servers? Often they can overheat. In a racked server environment, a hot/cold row design makes more sense because the air doesn’t flow bottom to top, but front to back. Therefore, if you place perforated panels in the aisles in front of the servers, you’ll be forcing air to through the front of the entire rack, which will give all the servers top to bottom access to the cool air. You’ll be able to more evenly cool the server components and pass the heated air through the back of the rack. The hot air will rise and be extracted by the air conditioning unit.