Packet Power CEO in Processor.com Article on DC Power -- July 20 2009
July 3, 2009 • Vol.31 Issue 18
Page(s) 30 in print issue
Measure & Track Server Power Consumption
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Monitor Systems For Better Management
IT departments continue to struggle with making sure there is enough power to keep the server room up and running. But without much granular data on how the equipment consumes electricity, power planning often remains a hit-or-miss proposition. However, smarter hardware and software that offer real-time monitoring to comprehensively track where and how electricity is consumed can offer opportunities to better manage and even reduce a server’s power draw.
Monitoring might reveal, for example, servers that account for a significant chunk of the data center’s total power feed but actually run idle most of the time. Or it may lead to the discovery of a cooling system that is over-consuming precious watts of power without keeping temperatures down where they should be. These are just a couple of things that tight monitoring can reveal, allowing for IT personnel to make modifications to get more performance out of the watts consumed. With electricity costs accounting for as much as 20% of IT budgets, according to Symantec, slashing power consumption by just a few percentage points can add up to major cost savings.
“The benefits can be very significant, with direct power cost avoidance often being enough to justify the power monitoring investment,” says Steve VanTassel, CEO of Packet Power (www.packetpower.com).
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Key Points
- Tracking power usage to eliminate waste can lead to huge cost savings.
- Hardware and software used for monitoring applications have recently improved and now offer granular measurements about data center power consumption.
- Despite advances in monitoring technology, it is up to the admin to make use of the data in order to make improvements.
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Getting Started
Before putting a comprehensive power monitoring system in place, it is important to assess what the data center’s power needs are. Everything that runs on electricity in and to the server room must be taken into account and tracked. All servers and related networking equipment necessitate the same level of scrutiny as equipment that is not directly related to IT does, such as cooling and the lighting infrastructure, says Robert E. Hanson, an innovation leader for IBM’s Systems and Technology Group. “Non-IT power can be up to 50% of the total power consumption of a data center, which is why it is also very important,” Hanson says.
It is also necessary to determine what you plan to do with the data before getting started and then design the monitoring system so it communicates information to meet those goals. “Determine what you need the information for. This will determine the level of granularity and accuracy you need,” VanTassel says. “If your goal is to establish a baseline, such as a PUE [power usage effectiveness] score, and to gauge improvement across time, it may be adequate to start with a basic monitoring of current at the rack level.”
Assessing what needs to be monitored before investing in new power-tracking equipment and software will offer a better idea of the costs involved, which can vary. “It is difficult to put a price tag on how much it will cost to implement a power monitoring system,” VanTassel says. “Costs vary widely depending on both the type of monitoring solution and the cost to take whatever action is needed to lower power consumption.”
The Hardware
Despite rising electricity costs and heat problems, admins still use rudimentary approaches to tracking power consumption.
“The tried-and-true method has always been to get a meter out and manually check circuits. This is labor-intensive, provides a current-only reading, can be hazardous on larger circuits (and as such require an electrician), gives a point in time reading only, and relies on the user to record the data somewhere useful,” VanTassel says. “In many data centers—particularly midsized facilities—this is still the norm.”
However, UPS (uninterruptible power supply) systems and PDUs (power distribution units) have begun to offer power usage measurements down to the outlet levels, meaning you can track electricity consumption of individual servers to know what specific servers are drawing.
“You can now get very granular detail on an outlet level about power consumption for individual servers, whereas just a year ago, you could only measure a circuit or a few servers together,” says Joe Skorjanec, technology manager for Eaton (877/785-4994; www.eaton.com).
But in addition to using UPSes and PDUs to measure server power draw, you need to use intelligent sensors, as well, especially for non-IT-related equipment. “[UPSes or PDUs] only give part of the power-consumption picture,” says Michael Petrino, vice president of PTS Data Center Solutions (www.ptsdcs.com).
Indeed, sensors can now track real-time power usage of non-IT equipment to complement UPS and PDU units. “The data center industry is in the process of instrumenting or adding sensors to all equipment so that a ‘management server’ can collect the power and thermal data,” Hanson explains.
Crunch The Numbers
In addition to PDUs, UPS units, and sensors, you need software that can aggregate, process, and analyze the data the hardware provides in such a way as to allow you to make decisions about how to curb power usage. You can incorporate the software into server management tools.
“Your server management software stack should have a layer that collects all the data from the hardware, a layer that manages and organizes all the data coming in from the sensors, and a layer that displays that data back to the data center operator, which perhaps shows thermal maps for hot spot detection, power usage, or efficiency calculations,” Hanson says. “Beyond that you may want analytical analysis of the data that would allow you to automate the management of [the data center] to allow for real-time decisions on data center management by the operator.”
The software should also offer Web and SNMP monitoring capabilities, Petrino says. “Start gathering and logging that data,” he says. “From there, look at SNMP and dry contact monitoring solutions that report back to some form of HTML Web interface.”
The Challenge
Smarter PDUs, UPSes, sensors, and other hardware designed to track power consumption used in conjunction with software that stores and trends data are indeed powerful tools that are also becoming more affordable for small to medium-sized enterprises. But challenges exist, especially when it comes to interpreting the huge aggregates of data that monitoring reveals.
“When you have [hundreds] or thousands of servers deployed, you gather a lot of data, so the challenge today is how to make sense out of all of this data that you have access to,” Skorjanec says. “Since many companies have cut their staff, there are fewer people trying to do more, and it is really challenging. You have these great products, but programming the software to get it to do what you want it to do is a challenge.”
Ultimately, it is up to the administrator to use the data in such a way as to make power-saving modifications to the data center. “The challenge from a user standpoint is taking all of these measurements from the software and logically making sense of what they are measuring.”
by Bruce Gain
Top Tips
- Determine what the server room’s true power capacity is and program the monitoring system to send alerts when limits are close to being reached.
Simplify the process by tracking the same type of power measurement, such as amperage, voltage, or watts, if combining data from different systems, says Steve VanTassel, CEO of Packet Power (www.packetpower.com).
- Make sure to use monitoring to take the appropriate action. Just learning about inefficiencies is the beginning step. “[Power-monitoring] data is useless if you do not have a strategy for improvement,” says Matt Kightlinger, director of solutions marketing for Emerson Network Power’s Liebert products business. “But even slight improvements in one area can lead to significant efficiencies down the power stream.”
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