Data center trend: Increase power density

Data center trend: Increase power density

At the data center design level, an important trend is to increase the power density. Given the space limitations of the data center, it needs to operate more efficiently to cope with the rise in power demand and costs. Obviously, putting more resources into each rack is a very practical solution. However, in addition to the inherent benefits of this solution, increasing the power density also brings some problems and challenges that must be solved by some data center operators.

Power Density Trend

Low power density is often equivalent to low efficiency. Such valuable space resources are only consumed by such a small amount of IT equipment resources, while they also consume more equipment maintenance costs. CFO and co-founder of Colovore, a high-density hosting provider in Santa Clara, noted: "Currently, the racks deployed by customers in typical data centers are about 8-12 KW series per rack, although some data centers have higher density requirements, the phenomenon of close to 20 kilowatts is still rare in most big data analysis and processing intensive applications. But at the same time, there are still some typical data centers in the United States along the coast with racks of 4-5 KW (which is the standard revised 10 years ago )."

In hosting space, it is very expensive to only support low-power density, because the full-rent Rack Space may not be available due to the lack of sufficient power. Although the rack is equipped with a large number of devices, the supporting capabilities of the hosting space infrastructure do not match. "Customers can easily deploy 8-10 KW of each rack on their existing server infrastructure, but because most data centers are designed to support only 4-5 KW, in this way, they must implement the operation of half-rack equipment across racks, otherwise they will not be able to implement cooling well. But the customer has already paid for the entire rack, even though it only uses half-rack load resources. This is undoubtedly a waste ."

One of the most obvious constraints on power density is power distribution infrastructure. The level of power supplies provided by public power companies and backup facilities in data centers will affect power density. For each watt of power provided by a public power company, the data center must have enough UPS and diesel generators to continue to maintain its operational capabilities in the case of power outages. Of course, wiring and distribution units (PDUS) provide power to dedicated racks. "Most data centers do not have much power to supply to their facilities, so they want to get more power resources from public power companies, and spent a lot of money on the core infrastructure of the data center (electrical and mechanical infrastructure, generators, distribution equipment, etc. Therefore, for data centers, obtaining more power and cost problems is two important variables ."

However, the data center may face a more urgent need of cooling: Each power consumed by the equipment will produce a waste of heat, which must be removed, to maintain the operation temperature required by the data center. This is also the biggest challenge that the data center initially did not intend to place the device into a higher density. "When the density of your data center racks increases, the server will generate more heat, so more cooling is required ." He said. "Cooling down infrastructure is very expensive, but the biggest challenge may come from trying to transform the old data center. In most of these old data centers, the roofs were low at the early stages of construction, and in many cases there was no simple way to increase density. In addition to demolition, there is almost no way, but it is very difficult for data centers, especially when they host some customers ."

Unfortunately, for traditional data center enterprises, transforming their data centers into data centers with higher density means that, in addition to waiting for improvements brought by semiconductor Moore's Law, its data center facilities have little practical potential to continue to expand computing capabilities. However, this method requires buying new IT equipment, better technology, and increasing Moore's Law to achieve higher efficiency, which may take about 10 years. In this case, "hosting providers can only simply use 'distributed load ', or force customers to use their infrastructure across half racks," he said. However, this is obviously not sustainable, and they will eventually exhaust their space, power, and cooling resources as the customer servers refresh ."

Integrated infrastructure drives greater power density

The promotion to higher density can be summarized into long-term infrastructure integration: basically, more computer resources can be packaged into smaller sizes, which can be achieved through the existing trend of the data center, such as virtualization technology, blade servers, and microservices. The integration of Infrastructure "plays a very positive role in the operational efficiency of data centers ." "Because the physical size of IT deployment is small, IT managers have limited management permissions, and when the number of servers is reduced by 30-50%, it makes more sense to save the total power."

This approach is designed to reduce the total power of the data center through the power of the hoist shelf layer (which has a dual benefit because it also reduces cooling requirements ). "In fact, the power demand for each server is greatly increased, but in general, the total power can be reduced because the number of servers required is smaller. This is why high-density data centers have become so important. They are the key to integrating all infrastructure. Today's servers can easily achieve 500 to 1 kw w per rack unit !"

Heat Dissipation problems caused by high density

Of course, high density can bring higher efficiency. Each rack is equipped with as many equipment as possible, which helps the data center to save as much cost as possible, occupy space and solve management problems. But good things all need to be weighed: in this case, it will cause cooling problems. Low-density deployment usually uses air cooling and, in most regions, free outdoor air cooling is used. However, as the power density of data centers increases, Air Cooling becomes prohibitive and expensive.

Compared with the evenly distributed direct cooling source, the hot production solution is more similar to providing a point source: The heat production is caused by the rack, server, or even processor level. "The server's chip-level processing capabilities seem to keep increasing, but in some cases they will need internal cooling and immediately implement cooling near the server to prevent too much heat from being produced ." Therefore, it may not be enough to use air cooling for a single point. Water resources (or other liquids) need to be used to provide greater cooling capabilities. However, this requires sacrificing part of the infrastructure delivery capability, there are also some difficulties in upgrading, such as strict isolation between cooling water and electronic components of equipment.

Deploying a water-based cooling solution may cause some problems, especially for older data centers, and the existing infrastructure must be transformed. However, for new facilities that support increasing power density, Water Cooling Schemes can deliver cooling capabilities to wherever they are needed, instead of simply trying to keep the entire room low enough to ensure the overall operating temperature of the server space. Such schemes as hot channels and cold channels can give air cooling room for maneuver, but they also have limitations. Finally, as the demand for high density of data centers increases, immersion technology may become necessary. Some companies are already offering products in this area, including non-conductive fluids, and entering the cooling liquid into the server chassis.

High-density return

For customers, whether they are customers hosting services or data center operators, high density can provide them with significant and lucrative profits in terms of total cost of ownership (TCO. "When a company can integrate its IT infrastructure to virtualized blade servers, IT can immediately save 20% to 30% of its operating costs, and 4-5 KW legacy deployment for each rack. This is largely because it saves the power cost of monthly cabinets to accommodate servers and reduces the cost of cross-connection and top-level rack switches ." For customers hosting services and data center operators, this means further expanding the available space of existing racks and selling out the trouble and cost for building new data centers, its benefits are not just direct cost savings.

For enterprises that want to continue to maintain their legacy data center buildings or hosting routes, they need to increase efficiency and save space on the ground and racks as energy prices increase and IT service needs increase. Therefore, the implementation of high-density power in data centers is a general trend, but it is also a challenge: to package more capacity into the rack requires the construction of relevant distribution equipment, backup infrastructure and cooling capacity also need to provide relevant deployment support to maintain the management operation temperature. Although the coolant method is not a common trend at present, it will become more common as air cooling methods gradually become less practical and affordable in high-density environments. However, no matter how long it takes from air cooling to liquid cooling, the power density of the data center will undoubtedly continue to rise as enterprises are trying to maximize the use of their resources.