Energy Efficiency: What You Can Do

While suppliers tout the energy efficiency of their products, buyers wonder, "What can I do to reduce my power bill?" Answer: It's only partly a storage product problem. Start by taking responsibility for the issue, and, contrary to popular wisdom, do sweat the little things.

The price of oil spikes and pulls all energy-related costs in an upward trajectory. The global oil currency (a.k.a. "the dollar") plummets, demand from emerging eastern economies spikes, and geopolitical turmoil in the Middle East creates a potent mix of energy inflation that is stinging corporations.

As a result, electricity costs are becoming a higher percentage of data center spend. But according to the Wikibon community, only 5 percent of CIOs actually pay for the power budget. So why should users care? The obvious answer: Boards of directors are taking notice. According to IDC, average data center energy costs are growing at 20 percent per year and are expected to double by 2012.

Discussions with Wikibon* users show a similar trend as shown in Figure 1 below.

Figure 1:

Compounding this problem is the fact that power density is going up between 20 and 30 percent for all IT equipment annually. This has the following ripple effects:

There is no end in sight to this vicious circle. The maximum heat density of equipment that can be air-cooled in a data center is approximately 10,000 watts per square foot, yet most data centers were designed years ago for power densities of much less than 1,000 watts per square foot. Many data centers are now constrained by power and cooling limits, not floor space as was the case last decade. The bottom line is todays data centers will largely be obsolete by the end of this decade as we are approaching the limits of heat extraction in many shops.

What can be done?

The three most useful actions organizations can take to reduce energy consumption are:

The effectiveness of using outside air will vary. If you’re in Tampa, Florida, for example, you might only see a 5 percent savings on cooling costs because of the humidity of the climate, but if your data center is in Fairbanks, Alaska, you could save over 60 percent.While many data centers are using hot and cold aisles, implementing air monitoring equipment can gauge its effectiveness. This is important, because when equipment is moved around or retired, temperatures will change, and such a technique can give managers more confidence to raise temperatures in the data center to the optimum level. Studies have shown that for every one degree you can raise the temperature in a data center, energy costs will be cut by 4 percent.

Consolidating servers and getting rid of older equipment through virtualization could make a substantial dent. According to Michael Crader, who heads Windows consolidation at U.K. telecom giant BT, his company was able to save $2.5 million annually on the energy bill, largely by virtualizing server infrastructure.

Unfortunately for storage managers, these three actions aren’t directly storage related.

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*The Wikibon Project, of which David Vellante is co-founder and contributor, is a research and advisory community of practitioners dedicated to the open sharing of business technology knowledge. Where Does Storage Fit in the Energy Equation?

While storage is often one of the fastest growing parts of an infrastructure, it’s not the most power consumptive. The table below shows the culprits of power consumption within the data center based on customer interviews within the Wikibon user community and some modeling done with input from electric companies.

Table 1: Data Center Power Consumption

The following findings are relevant:

The most important fact to remember is that if you only focus on air conditioning and power distribution you’re missing half of the problem – the IT equipment itself. Addressing the IT piece of the pie automatically allows the temperature of a data center to be raised, creating more bang for your buck.Storage, while only one part of the problem in the data center, is meaningful. Within the storage stack, the main culprit is spinning disk drives, accounting for an overwhelming 80 percent of the power consumption of storage arrays on average (see figure below).

Figure 2:

Customers should note that this figure will be lower for controller-intensive tier-1 arrays (more like 60 percent).

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What can be done? According to William Souder, director of network operations and chief security officer at Berry College in Atlanta, “There is no silver bullet when it comes to energy efficiency. Customers must evaluate a variety of alternative techniques to reduce power consumption and choose the ones that best fit their requirements.”

In general, with storage consumption growing at 50 to 60 percent per year for many customers, and budgets flat to down, the best approach is to find techniques that help consume less storage and/or use storage more efficiently. The other broad technique is to get rid of equipment that is power hungry and to modernize infrastructures.

Here are seven approaches (with associated tradeoffs and caveats) that storage managers can consider to reduce the energy bill.

Classify, migrate & delete

You typically won’t hear vendors lead with this one but from a storage perspective, the root cause of increased energy consumption is that organizations store far too much unnecessary information, including worthless pictures, .pst files that contain junk emails, and truckloads of file versions that will never get accessed. The most important action storage managers can take is to classify information, move data to less power hungry devices and get rid of stuff you don’t need. According to Wikibon users, 80 percent of data never gets accessed after 90 days. Crader’s BT has a policy within his group that after 90 days, data is deleted unless users specifically request a higher threshold. While this policy won’t fly in all industries, in many cases, users keep many duplicate copies of data that has zero business value.

Beyond this critical step, which is usually put on the back burner in favor of other techniques, other storage practices and approaches can be used to address energy consumption and buy some time. Read on.Storage virtualization & thin provisioning

Not nearly as high-impact as server virtualization, these features bring the benefit of better storage utilization, ease of backup, and simplified maintenance and provisioning. They also bring complexities, including performance management. Often, they require redesigning major processes in a data center.

Tiered storage can take advantage of ultra-high-capacity SATA devices and match device characteristics with data access frequency and availability requirements. But it’s not always easy to tell business users that their data is being moved to "tier 2" (a.k.a. “You’re not moving my data off tier 1”). Also, restoration times on large-capacity devices are exceedingly long, often necessitating power-hungry replication infrastructures – which defeats the purpose.

Data de-duplication
As applied to backup or online archiving, data de-dupe can demonstrate disk reduction ratios of 10x to 15x for backup or 2x to 3x for online storage. However, disk-based backup using de-duplication is designed to replace tapes, which are the greenest of technologies (notwithstanding transportation impacts and the rising price of gasoline).

MAID/spindown

Techniques that idle drives for inactive data are an effective approach, but increasingly, organizations are wide-striping data across multiple disks for performance and resilience. This means all devices are always active and can’t be idled, so spindown infrastructures should be isolated from high-performance storage.

NAND & Flash

These technologies are making inroads into conventional disk drives and if you can cost-justify the technology it will save on power relative to spinning media. Durability and maintenance impacts remain key concerns.Energy rebates

Customers should take advantage of energy rebates and credits where available. To date, there are a handful of power companies offering incentives for installing more energy-efficient storage, including PG&E of Northern California. However, according to Mark Bramfitt, program manager of PG&E’s IT incentive program, “Not many storage vendors are taking advantage of the initiative. To date, no customer has received an incentive rebate for installing more energy-efficient storage equipment.” This is largely because storage vendors haven’t bothered to qualify for the program.

Green carrots & sticks
Green initiatives may require an initial capital outlay, giving pause to financial managers. However, in this day and age they bring inherent appeal. As such, organizations should use green initiatives as a catalyst to modernize infrastructure which can lead to better ROI (e.g., server and storage virtualization). By linking green to a corporate initiative and marketing it internally, IT managers can ride the coattails of CEO edicts.

A critical success factor is cohesion between IT and facilities. These groups have different goals today and need to be aligned for green initiatives to thrive. Establish cross-functional teams and partnerships within IT and the business, with representation from infrastructure groups in IT and the energy experts in facilities management. Bridge the two perspectives, and begin designing power and cooling considerations into virtually all decisions, understanding the tradeoffs and benefits. Vendors can be helpful in this process if you can get past the product hype.

Managers should consider treating green initiatives like a normal project with clear measurements, solutions, and timelines for reduction in power consumption. Remember, ultimately the goal is to reduce the energy bill which can be leveraged within IT and marketed to the business.

David Vellante is a co-founder and contributor to The Wikibon Project (http://www.wikibon.org), a research and advisory community of practitioners dedicated to the open sharing of Business Technology knowledge. 0