The power of virtualization

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If companies needed another reason to get going with storage virtualization, here it is: Pacific Gas and Electric...

Co. (PG&E) announced in November it's offering rebates to companies that implement virtualization in their IT departments. And while the announcement seemed to indicate the utility was concentrating on server projects, storage virtualization can be eligible for the rebate as well.

"Any virtualization effort that results in energy savings is eligible [for the rebate], regardless of platform or software," says Mark Brantiff, supervisor of the high-tech segment of the customer energy-efficiency program at PG&E. The key, he says, is that companies must apply for the incentive before starting the work. That step is critical; the incentive can't be paid if the application is submitted after virtualization is up and running because the savings can't be assessed.

Storage virtualization is one of the top recommendations made by vendors and analysts for reducing power and cooling costs, and keeping the storage footprint as small as possible. Putting heterogeneous devices behind a virtualization product allows you to pool storage, allocate capacity more efficiently and perform data migration more easily. This slows down the rate at which you add capacity, and increases the utilization of the capacity on hand.

Making better use of installed storage may require more power, but that's offset by deferring new purchases. "[Let's say] you're going to run a device at X in terms of power and cooling," says John Webster, principal IT advisor at Illuminata. "If that device is running at 30% and it costs you X to run it, if you drive it into 60%, does that cost really substantially more? Probably not."

In tandem with virtualization, storage that's tiered within a single frame can further increase energy efficiency. Several vendors offer this capability; for example, Hitachi Data Systems (HDS) offers it in its TagmaStore systems; IBM in its DS4700 and DS4800 midrange systems, as well as in several of its Turbo systems; and EMC offers it in the DMX-3 series.

Rajeev Gagneja, technical director at Intellidyn, a consumer marketing intelligence provider in Hingham, MA, has an HDS TagmaStore AMS500 housing three storage tiers comprising approximately 21TB of data. According to Gagneja, using a separate cabinet for each tier of storage would require at least six 30-amp circuits, each costing approximately $1,000 per month. He's using two circuits and significantly reducing his storage space with one box.

"That gives me good flexibility and creativity in terms of keeping my cost down for power, and also keeps my costs down in terms of rack or real-estate space," says Gagneja. He adds that he'll be starting a virtualization project in the second quarter of this year, and expects he'll be able to shrink his storage down from the four-and-a-half racks currently in use to two.

By and large, vendors and analysts agree that virtualization should be one of the first items to consider when looking at energy costs, and PG&E's announcement bolsters that sentiment. But most caution users not to overlook other available options that can drive up capacity utilization. These include single-instance storage and even evaluating policies around how many production data copies a company needs to have on hand, says Patrick Eitenbichler, director of marketing at Hewlett-Packard's StorageWorks Division.

"Some vendors feel that virtualization is a panacea to all storage problems," says Eitenbichler. "[But] there are many ways to increase utilization and reduce the capacity needs for a storage customer."

--Trina MacDonald

This was last published in January 2007

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