Reporting Electricity Consumption

As the energy prices go up and people realize that electricity production has also an ecological cost, IP departments recently started to look attentively to their electricity bill. In most cases, it's higher than expected and it is impossible to know which component in the IT infrastructure is consuming the most: the servers, the storage, the network, or the server room itself.

As the demand for more energy efficient servers grew up, server manufacturers started to release servers that were optimized with the electricity consumption in mind. To prove their point, server manufacturers finally instrumented their servers so that they were able to report their energy consumption “live”. Hardware Sentry KM leverages this information and expose it with the PowerConsumption parameter (in Watts) on the Enclosure class and as a total in the Capacity Report object.

However, if most recent servers report their energy consumption, older one do not, and cannot benefit from any service pack or firmware upgrade to implement that functionality. If you want to know how much electricity is being consumed by an older server (or a really recent server, but not instrumented this way), you will need to use a physical power meter plugged between the server’s power supplies and the wall plug.

Starting with version 1.6.01 of Hardware Sentry KM, our product is able to estimate the power consumption of a server, based on its internal components. By knowing the characteristics of the different hardware components (processor model, maximum speed, current speed, number of memory modules, network card activity, etc.), Hardware Sentry KM provides you with a fairly accurate estimation of the electricity consumption (in Watts) of any monitored device (server, disk array, fiber switch, etc.).

When a server is not able to report its power consumption, the PowerConsumption parameter is not displayed under the Enclosure icon. It is only displayed under the Capacity Report icon. By visualizing the history of the PowerConsumption graph in the PATROL Console, you can observe the kind of activity that makes your server consumes more energy, if that is the case.

If you know the electricity consumption for a server for which Hardware Sentry KM cannot automatically collect or calculate this value, you can enter this information in the system manually. Right-click the Hardware icon > KM Commands > This System's Settings > Default Power Wattage.

The Default Power Wattage feature allows you to enter the electricity consumption for a given device. Simply enter this value in Watts and Hardware Sentry KM will use this information in the Energy Usage Report as well as for reporting the PowerConsumption parameter value.

One interesting way to exploit this information is to compare the PowerConsumption parameters of many different servers and see which ones (which brand) are the most energy wise. Knowing which type of servers consumes less energy can be an important decision factor when purchasing new servers.

While much attention has been paid to obtain the best accuracy possible in the power consumption estimation done by the KM, comparing an actual value (read from an electricity sensor) and an estimated value may lead to unexpected results.

In order to better understand the electricity bill, Hardware Sentry KM 1.6.01 provides an Energy Usage report in kWh. Right-click the main hardware icon grouping the hardware components of a given server > KM Commands > Reporting > Energy Usage Report…. Select a “daily” report for a several day period of time. The graph displayed in the PATROL Console shows the electricity that has been consumed by the device for each day. If you know the price of the kWh in your region, you can easily calculate the energy price for the server.

PowerConsumption is expressed in Watts. It’s an instantaneous value, very much like a speed or a rate (megabytes/sec, e.g.). It represents how quickly the server is burning energy for its operation. The “Energy Usage” report is expressed in kWh (kilo Watt hour). It represents the amount of energy consumed by the server in the specified interval (hour or day). The Energy Usage report in kWh is to the power consumption what distance is to speed: Energy = Power x Time.

When it comes to lower the electricity bill, the very first step is to measure the current energy consumption. As Lord Kelvin put it: “If you cannot measure it, you cannot improve it." Then it is very interesting to observe what can have an impact on the power consumption of a given server. You can use the data collected by Hardware Sentry KM 1.6.01 to correlate them with other KMs or external data. You may realize that the deployment of a specific application can have a significant impact of the electricity consumption, because of its activity (an anti-virus program, for example).