|
|
Africa: Apc-Mge Addresses Cooling Problems
 |
|
|||||||||
|
||||||||||
Highway Africa News Agency (Grahamstown)
19 October 2007
Posted to the web 19 October 2007
Zachary Ochieng
High-density servers present a significant cooling challenge, with vendors now designing servers that can demand over 20 kW of cooling per rack.
With most data centres designed to cool an average of no more than 2 kW per rack - innovative strategies must be used for proper cooling of high-density equipment.
APC-MGE has put together ten steps that address the root causes of cooling inefficiency and under-capacity, listed in rank order, with the simplest and most cost effective presented first.
According to Carl Kleynhans, APC-MGE's Africa regional director:, Step number one is to perform a health check. Before embarking upon expensive upgrades to the data centre to deal with cooling problems, certain checks should be carried out to identify potential flaws in the cooling infrastructure.
These checks will determine the health of the data centre in order to avoid temperature-related IT equipment failure. They can also be used to evaluate the availability of adequate cooling capacity for the future.
The current status should be reported and a baseline established to ensure that subsequent corrective actions result in improvements.
A cooling system checkup should include the following items: maximum cooling capacity; CRAC (computer room air conditioning) units; chiller water/ condenser loop; room temperatures; rack temperatures; tile air velocity; condition of subfloors; airflow within racks; and aisle and floor tile arrangement.
Step two is to initiate a cooling system maintenance regime. Regular servicing and preventive maintenance is essential to keeping the data centre operating at peak performance. If the system has not been serviced for some time then this should be initiated immediately.
A regular maintenance regime should be implemented to meet the recommended guidelines of the manufacturers of the cooling components.
The next step would be to install blanking panels and implement a cable management regime. Unused vertical space in rack enclosures causes the hot exhaust from equipment to take a 'shortcut' back to the equipment's intake.
This unrestricted recycling of hot air means that equipment heats up unnecessarily. The installation of blanking panels prevents cooled air from bypassing the server intakes and stops hot air from recycling.
Airflow within the rack is also affected by unstructured cabling arrangements, which can restrict the exhaust air from IT equipment.
Unnecessary or unused cabling should be removed, data cables should be cut to the right length and patch panels used where appropriate and power to the equipment should be fed from rack-mounted PDUs with cords cut to the proper length.
Step Four is to remove under-floor obstructions and seal the floor. In data centres with a raised floor, the sub-floor is used as a plenum, or duct, to provide a path for the cool air to travel from the CRAC units to the vented floor (perforated tiles or floor grilles) tiles located at the front of the racks.
This subfloor is often used to carry other services such as power, cooling pipes, network cabling, and in some cases water and/or fire detection and extinguishing systems. During the data centre design phase, design engineers will specify the floor depth sufficient to deliver air to the vented tiles at the required flow rate.
Subsequent addition of racks and servers will result in the installation of more power and network cabling. Often, when servers and racks are moved or replaced, the old cabling is abandoned beneath the floor.
Air distribution enhancement devices can alleviate the problem of restricted airflow. Overhead cabling can ensure that this problem never even occurs. If cabling is run beneath the floor, sufficient space must be provided to allow the airflow required for proper cooling. Ideally, subfloor cable trays should be run at an upper level beneath the floor to keep the lower space free to act as the cooling plenum.
Missing floor tiles should be replaced and tiles reseated to remove any gaps. Cable cutouts in the floor cause the majority of unwanted air leakages and should be sealed around the cables. Tiles with unused cutouts should be replaced with full tiles and tiles adjacent to empty or missing racks should also be replaced with full tiles.
|
The fifth step is to separate high density racks. When high-density racks are clustered together, most cooling systems become ineffective. Distributing these racks across the entire floor area alleviates this problem. The fundamental reason why spreading out high-density loads is effective is because isolated high power racks can effectively 'borrow' underutilised cooling capacity from neighboring racks. However, this effect cannot work if the neighboring racks are already using all the capacity available to them.
|
| |||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||
|
| |||||||||||||||||||||||||||||
|
| |||||||||||||||||||||||||||||
| Make allAfrica.com your home page | RSS Feed | |||||||||||||||||||||||||||||
|
| |||||||||||||||||||||||||||||
| Top | Site Guide | Who We Are | Advertising | Search | Subscribe | |||||||||||||||||||||||||||||
|
| |||||||||||||||||||||||||||||
| Questions or Comments? Contact us. Read our Privacy Statement. | |||||||||||||||||||||||||||||
|
| |||||||||||||||||||||||||||||
|
| |||||||||||||||||||||||||||||
