July 2012

Data Center Efficiency

Every device counts! Measuring Energy Efficiency in Data Centers

By: Dr. Ben Eshay

It seems only a few years ago that we heard environmental organizations pushing us to move to a “paperless” society in order to save those trees and rainforests from extinction. How ironic! Yes, some trees may have been saved, but arguably, the impact of waste disposal, energy power consumption and carbon dioxide (CO2) emissions are much more significant threat to the environment than paper consumption. The amount of power now needed to sustain this “new” paperless society is mind-blowing – a far cry from ‘just’ cutting down trees. Microsoft estimates that a 200 kilowatt prototype data center will emit more than two million pounds of CO2 emissions per year – which it says is equal to 300 Honda Civic cars. “Paperless” giant Google says that its data centers use about 2.3 billion kilowatts of power alone – equivalent to the power consumption of about 200,000 homes.

Reducing power consumption has become a top priority for most businesses. According to a survey by Symantec Corporation , about 97% of businesses were at least discussing green IT and a further 45% had already implemented one or more green IT projects.

One Center, Many Concerns

Power consumption is only one of many concerns for the data center and communications room personnel. Another critical problem that has developed over the years is how to cool equipment within the data center. As more devices are added, more heat is generated and thus, more power is consumed. The Uptime Institute reported that more than 70% of the energy savings opportunities in data centers are in cooling equipment.

There are further non-environment related matters for management to seriously consider. Disaster prevention is one such example. A recent incident in metro Atlanta, Georgia accentuated this problem when a power outage shut down access to dozens of state agency information systems, due to a power surge in routine maintenance that had caused all the state systems to go offline – the most critical of which was the state’s criminal data base. Detention centers had to be extra careful not to release any criminals unnecessarily, or keep those jailed illegally.

The cost involved in maintaining data centers and communications rooms is another key cause for concern. Gartner estimates that a “small” 8,000 square-foot data center costs $1.6 million a year in power, with that figure only expected to rise. With energy making up 70% of the data center’s operating costs , reducing power seems the first port of call.

Calculating Power

Unfortunately though, knowing how much power devices are consuming is not enough. In order for power considerations to be an integral part of data center planning and ongoing operations – one needs to know exactly how much power each device is consuming at any given time. And even this is not enough. One needs to be able to see and control the power status of each device at any time, from anywhere.

When organizations look at reducing power, most begin by looking at its power usage effectiveness (PUE). In order to calculate PUE however, one needs to know exactly how much power the IT equipment in the data center is consuming. PUE can be calculated accurately with a Power Distribution Unit (PDU), which is an electrical device used to measure and control the distribution of power to individual loads. The PDU may be a stand-alone device or it may be integrated directly into the uninterruptible power supply (UPS). Knowing the data center’s PUE, the IT manager will be able to establish how much power is being spent on specific aspects of the data center (such as cooling). Cooling plays a critical role in achieving the optimum environmental levels for efficient IT however, cooling in itself consumes a lot of power.

Since the PUE metric was proposed, it has become an important standard as part of the Green Data Center Initiative. Measuring power levels is now just as important as measuring network performance. It is also recommended that cabinets and racks are provided with power strips that enable monitoring of power levels. This ensures that power consumption in the enclosures does not exceed the enclosure’s designed power and cooling limits. The cabinet and the data center should be fully balanced with respect to power consumption levels, if they are not, the PDU should immediately pinpoint the problems, helping the data center manager to solve the issue. In addition, fully controlling the IT components, including maintenance (with a device such as a PDU), prevents downtime before it actually it happens.

Integrating Power Measurement

Integrating the PDUs within a larger management system, such as Data Center Infrastructure Management (DCIM) has many benefits. Managing a data center requires steering a course through multiple, often conflicting, demands; power and cooling are only two of these considerations. Data Center Infrastructure Management (DCIM) offers an attractive solution for managing the overall assets, resources and status of the data center. With a DCIM power, cooling, space, servers, networking and storage can all be maintained.

Since different communications rooms and data centers require different degrees of power control and management, PDUs vary greatly and consist of:

  • basic PDUs
  • metered PDUs
  • smart PDUs
  • switched PDUs

Basic PDUs are implemented when monitoring and/or management is not needed. They provide a reliable and economic power distribution solution, supporting multiple outlets, voltages and configurations. The role of these PDUs is as electrical circuit breakers, which will prevent voltage spikes from causing the computers or networking equipment in the cabinet to malfunction.

Metered PDUs feature an additional easy-to-read, on-device display showing the current power load. These PDUs have the ability to read the current consumption of the entire data center.

The more advanced smart PDUs are exactly that: intelligent power distribution units within the cabinet. They offer real-time monitoring of power consumption, even remotely via a built-in web servers or dedicated software. Some vendors supply two smart PDUs that can be linked with one common IP address, reducing costs and freeing up switch ports. For basic environment monitoring, there is also no need for external controllers as key environmental parameters can be monitored by attaching two temperature and/or humidity sensors.

Switched PDUs offer everything the Smart PDUs do, with the ability to remotely switch on/off individual and multiple ports in the PDU. In some instances, SNMP enabled smart power strips are combined with the appropriate management software to provide the capability to record and analyze industry efficiency metrics such as PUE or Data Center Infrastructure Efficiency (DCiE)

Placing Everything in One System

DCIM is not a new concept. Until now however, DCIM simply offered management software and integrated third-party hardware to provide distributed hardware monitoring. This meant that “management” of devices in the cabinet was only restricted to a certain level of information. What was lacking was one holistic solution – something that would bring everything together in one manageable, coherent place. All aspects of the data center needed to be united on one platform – connectivity, network, assets, environment, power and cooling.

Recently a new DCIM offering has been introduced by RiT that unites all the critical components together, providing a robust, highly versatile platform for intelligently managing every aspect of the data center. This includes power and cooling management with maximum ease, efficiency and productivity.

The PDUs that are integrated into this DCIM are suited to a variety of requirements in data centers. They provide versatile density support, offering both single-phase and three-phase configurations for use across the globe. They are space-efficient and can all be zero U-mounted on the back or side of the cabinet. The software enables all connections to be viewed from anywhere, at any time with alerts triggered when problems arise. This enables immediate action to be taken to mitigate power problems, avoid further disasters and minimizing downtime.


It is without a doubt that the data center is one of the most power-hungry facilities. With server densities on the rise, server racks increasing their power loads and more cooling equipment used, an intelligent solution is required. It is good to know that finally, our paperless society has a comprehensive solution that not only allows us to see and control the power status of each device in the data center, but also, from anywhere, at any time.

DCIM with integrated PDUs provide a flexible solution for properly monitoring and managing power usage. It also assists in addressing other challenges such as enabling efficient and effective monitoring and management of the data center. A DCIM that offers both hardware and software together, enables organizations to adopt a comprehensive DCIM without complex integrations. This means that there is one point of management for everything – equipment, environment and power. IT personnel not only gain real-time power consumption monitoring capabilities (at the per-device level), they also acquire optimal provisioning, disaster prevention, green credentials and remote management.

Dr. Ben Eshay is CTO of RiT Technologies. For more information about RiT Technologies’ CenterMind P+ power management solution, please visit: http://www.rittech.com/p_plus