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Reserve Your Seat TodayMost people know why a server room should be cold. But, cooling server rooms is a never-ending battle. Effective cooling is important not only for the servers but also for associated networking equipment and power supplies.
As technology continues to observe Moore's law, and both processing power and energy draw per square foot increase, it gets warmer and finds new ways to confound your room's environmental systems. What are server rooms cooling solution best practices?
You can't simply let your servers run at high temperatures for fear of damage. Nor can you let your server room or data center suffer high or low humidity, which can short circuit your equipment. While this sounds easy enough, as equipment pushes 750 watts per square foot, it isn't enough to simply crank up the air cooling unit and expect your room to stay cool.
The air in your server room, especially nearest the processors in your equipment, will rise to dangerous temperatures quickly if not properly cooled and circulated. Without adequate cooling, your room also risks failing critical design considerations for airflow management. You don't want your servers and rack-mounted equipment taking in the hot air exhausted from other servers. If you do, you're likely to see equipment failures, or - at the very least - inefficient server activity.
Even if you had enough ac units that you could keep your server room at a reasonable temperature, you would expend a costly amount of energy doing so. Proper power supplies and temperature monitoring can prevent overheating and power waste. There are far more efficient ways to keep your room cool.
You may know it's important to keep your server room and equipment cool, but you may not fully understand the reason. Proper cooling is essential for the longevity of both computer servers and networking equipment.
Extreme heat and high humidity can cause major damage to your mission-critical gear. In the case of high-heat, many of the components in your equipment are only rated to operate within a specific temperature range. If your server room temperature exceeds that limit, pieces of your equipment can cease operation - or worse, fry completely. This causes permanent damage.
For humidity, it is a known fact that water and electronic equipment do not mix well. Protecting your physical security systems and whatever cabling runs within your room from moisture buildup is equally important.
Your equipment can handle a small amount of water that is naturally in the air. But, if the humidity hits a certain percentage, you're in for some trouble. If the humidity levels in your server room get too high, the water in the air can cause your equipment to have electrical shorts.
While you may get lucky just drying it out, most of the time the water renders the equipment permanently damaged. As a result, you'll need to replace the equipment. To save yourself from having to replace expensive equipment due to preventable damage, make sure your server room is appropriately monitored.
Even with state-of-the-art cooling systems, server rooms are not immune to failures that can lead to disastrous consequences. Understanding the most common cooling system failures and how to prevent them is essential for maintaining your room's uptime and efficiency. This includes ensuring all equipment - such as power supplies and fire suppression systems - is functioning optimally.
Blocked Airflow
Dust, debris, and improperly placed equipment can obstruct airflow, causing uneven cooling and hotspots in your server room. This not only leads to equipment overheating but also makes your cooling systems work harder than necessary.
CRAC Unit Failures
Computer Room Air Conditioner (CRAC) units are critical for temperature control, but mechanical issues such as compressor failures or refrigerant leaks can lead to rapid temperature rises.
Humidity Control Malfunctions
Improper humidity levels can cause condensation or static electricity - both of which are detrimental to electronic equipment. Humidity control systems sometimes fail due to sensor calibration issues or dehumidifier malfunctions.
Power Supply Issues
Cooling systems rely on uninterrupted power. Power outages, insufficient backup systems, or short-cycling due to power fluctuations can cripple your environmental controls.
Insufficient Cooling Capacity
Rapid expansions in server workloads or equipment density can overwhelm your cooling systems, leaving critical areas undercooled.
Liquid-cooled systems can help cool things down. Liquid-cooled systems run chilled water or liquid coolant through coils near, on, or through your servers and racks to keep them cool.
These sorts of systems are often rack-mounted closed-systems. They refrigerate and recycle coolant as it passes over, under, and around your hot equipment. Of course, liquid cooling is pricey and adds bulk to your server room.
Air conditioning systems in the server room are much cheaper. However, they simply won't do as good of a job unless arranged in ways to maximize cooling potential. Cool air flow has to be controlled. There also has to be a way to ensure that the servers intake cold air, exhaust hot air and that they don't exhaust their hot air into the intakes of other systems.
To deal with this problem, server room technicians and managers are looking to hot aisle strategies to help control airflow. In this strategy, servers and racks are placed in rows with their air intakes facing each other and exhaust facing away. This causes alternating hot and cold aisles.
Cold air is pumped through holes in the raised floor in cold aisles. Servers take in the cold air, exhaust it into hot aisles. In the hot aisles, CRAC (computer room air conditioner) units draw in the hot return air and cool it as it's pumped back below the raised floor to re-enter the system.
Server room cooling relies on a number of different variables. These include airflow, humidity, return, and equipment distribution. Your room requires carefully placed sensors and environmental monitors to stay ahead of potential failures. That's why you'll need to monitor the effectiveness of your room's environmental systems in many places.
You must ensure that the system is working properly. You can't simply leave environmental monitoring to the environmental controls in the room. Since they're placed only in areas where cooling, airflow, and humidity are most easily controlled, they prove insufficient.
Just because everything is fine with your CRAC units doesn't necessarily mean that the cold air is being distributed to the right spots in your server room. Humidity may be fine in your return-air space, but on the server room floor, at a different temperature, you may measure something different. Uneven temperature zones can stress power supplies and other sensitive equipment. The varied environment of the room demands that you spread sensors and monitoring equipment throughout your server room.
Of course, distributing sensors in the server room is no easy task. There are three major strategies to monitoring your room:
To monitor various spots in the room from a single device, DPS Telecom makes the TempDefender. The TempDefender is a small, rack-mountable remote telemetry unit (RTU) that can handle up to 16 analog sensors reporting on all of the environmental factors in your server room.
Sensors for the TempDefender may be daisy-chained together, so you don't have to run a mess of cabling back to the TempDefender. You can also string sensors up to 600 feet away from the RTU. This allows you to run sensors to the most extreme spots in your room from a centrally located device without worrying about connectivity issues.
Be careful if you measure your server room cooling system this way. Be sure to run sensors to spots likely to be hot. These include above equipment, hot aisles, and near your hottest racks.
You should also place sensors where airflow is most necessary. This can include hot air aisles on both sides of your cold aisles.
This will ensure even cold air distribution. You want to ensure that air, both cold and hot, is being effectively moved through the system. Losses and inefficiencies result in hotter rooms and more energy expended in the cooling process. While this isn't as bad as a complete meltdown, it's still not optimal.
If you're looking for a rack-to-rack solution, you should consider something like DPS Telecom's NetGuardian 216 G3 remote. The unit has four analog inputs, with which it measures the environment within the rack (or string sensors across a few racks). The device also has 16 discrete alarm inputs so you can directly monitor your servers and other equipment.
The NetGuardian 216 provides a total solution. With it, you can monitor environmental sensors and the dry contacts coming directly from your servers. This way, whether your problem is environmental or otherwise, you'll know about it.
Installing RTUs on every rack is the pricier solution. While it provides direct monitoring for your servers, which will help you ensure their safety and continued function, it doesn't necessarily tell you much about cooling systems in your server room beyond whether or not they're adequate. Measuring individual servers and racks will not likely clue you into inefficiencies in the system.
DPS also offers a line of sensors that operate seamlessly with your RTU to give you complete environmental visibility of your server room. The D-wire sensors feature temperature, humidity, and airflow measuring capabilities and up to 16 sensors can be daisy-chained together. Sensors allow you to monitor your room conditions instantaneously so that you can fix a problem before its too late. Other sensor options include temperature sensors with a probe, non-D-Wire analog temperature and humidity sensors, smoke detectors, and exterior weather sensors.
Combining both strategies with the TempDefender, NetGuardians, and sensors will give you the most complete view of the state of your server room. While it may seem like a large investment, you can't afford to leave your equipment vulnerable to damage.
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