Why Power Monitoring & Metering are Key to Data Center Efficiency

When we talk about data center efficiency, we’re really talking about the efficient use of power. We don’t want to waste energy, we want to save costs. That’s why energy efficiency is one of the main success factors driving the design of the data center.

We’ve all heard the saying, “you can’t improve what you don’t measure.” It sounds simple, but it’s really true. You have to constantly measure power consumption and have software behind the scenes that records the data and allows you to create useful reports. If you measure just once a week, for example, you won’t necessarily spot peaks in usage or know what’s causing them. You need to be collecting power data every few seconds.

You also have to determine where you’re going to measure power in the data center. You can drill down into separate rooms, or rows of cabinets, but ideally you will monitor power at the cabinet level. What is the power consumption? Is there enough power to support peak loads? Can we add more equipment? You need to know the answers to those questions for a very practical reason — so you don’t overload the circuit and cause downtime.

In order to measure power consumption, you will need intelligent power distribution units (PDUs). In most cases, it will be sufficient to install PDUs that can measure the total power usage in the cabinet. There are also PDUs that measure power at each outlet, which tells you what’s going on at the device level. But for capacity planning and power stability you just need the total power usage per cabinet.

Intelligent, rackmount PDUs connect to the network using standard communications protocols. They also have a web-based interface — you can log into them using a browser and see what’s going on. Some PDUs store data locally, and you can download the information into a spreadsheet. But a better solution is to connect the PDU to a separate monitoring system, such as a data center infrastructure monitoring (DCIM) platform. These systems will collect the information into a database and allow you to run reports showing power trends over a period of time. It’s very interesting to see exactly what’s going on and how changes to the equipment affect power consumption.

Once the intelligent PDU is constantly measuring power, you can set thresholds that allow you to get an alert long before you reach an overload situation. You could say, for example, “send me a warning if power usage exceeds 50 percent.” This will give you some time to take a closer look at what’s going on in that cabinet.

When we help customers design their data centers and server rooms, we always recommend intelligent PDUs. Yes, they cost more. It’s an investment. But the benefit is greater power stability and uptime. Intelligent PDUs allow you to constantly track the overall power usage of your data center, which positions you to work toward a more modern design.

Not all customers agree with that — there’s still a market for basic PDUs. Increasingly, however, organizations are recognizing the advantages of power monitoring. You don’t really think about the power coming out of an outlet, but in the data center it’s critical to understand how much power is being used in order to optimize costs and reduce the risk of downtime. You can’t improve what you don’t measure.