Solid-State Drives In The Data Center

It's no secret that data centers are power-hungry beasts. Here are some widely acknowledged facts about the current energy consumption of data centers:• Incremental U.S. demand for data center energy between now and 2010 is the equivalent of about 10 new power plants • Worldwide energy consumption of the data center doubled between 2000 and 2006 • Data center electricity consumption is almost .05% of world production • The average data center consumes energy equivalent to 25,000 households • The average cost of utilities for a 100,000-square-foot data center is running at a staggering $5.9 million annually.

One option on the horizon for companies who need to address data center energy consumption for certain high-performance applications is solid-state drives (SSDs), says Brian Beard, strategic marketing manager with Samsung Semiconductor. These applications can include Video on Demand, virtualization, Web serving, and OLTP (online transaction processing), which currently use 15,000-rpm hard disk drives (HDDs) that are 'short stroked,' or use only the outmost diameter of the drive to optimize performance. For these performance-oriented applications, Beard says a single SSD could replace several short-stroked HDDs. "SSDs require one-tenth or less of the power consumed by enterprise-class 15,000rpm hard drives in servers. They also enable faster IO/PS [Input/Output operations Per Second] performance and faster read and write speeds, for quick access to 'hot' data," he says. SSD drives also have the advantage of not having moving parts so they create hardly any heat, and thus do not require the standard cooling equipment used in today's data centers. Beard says that in high performance environments (roughly 10% of the market), short-stroked drives render total capacity utilization rates as low as 20-25% and that adopting SSD for this 10% of the market would save $1.2 billion in drives alone (assuming 4.6 million total drives at $300 each and a 1:10 replacement rate).

Beard uses a real-world example from a Samsung client who uses both SSDs and HDD in a complementary Video on Demand application, where "hot content" that needs the fastest possible IO/PS (streaming new releases or the most popular movies) relies on performance-optimized SSDs while "cold content" that needs the largest possible capacity for storing thousands of classic movies uses capacity-optimized HDDs. In this particular VOD application, SSD allows 70% power savings and 80% space savings.

The biggest barriers to adopting SSDs in the data center have been price and capacity since HDDs are much less expensive and hold much more information. For example, a server-based HDD costs $1 to $2 per gigabyte, while SSD costs from $15 to $90 per gigabyte, according to IDC.

Jeff Lowenberg, VP of facilities for Houston, Texas-based hosting provider The Planet , agrees that from his price-per gigabyte perspective SSDs are priced at a premium versus traditional HDDs and most data centers would be hard pressed to justify the cost premium for SSD-based systems. Price is especially an issue for The Planet, according to Lowenberg, since The Planet's hosted model offers a 75% cost savings compared with do-it-yourself alternatives. Over the past two years, The Planet has aggressively expanded its data center footprint to 7 data centers totaling 253,500 square feet, including a new co-location facility accommodating approximately 8,000 servers that will open in May 2009. Capacity is another reason to stick with HDDs, Lowenberg says, since The Planet offers storage options ranging from 256 GB to 10 TB for customers with large database and archiving needs, capacity that is far in excess of that available on SSDs.

While SSD solutions make the most sense in applications where the benefits of SSDs match those of the market application, data center managers will want to keep an eye on the horizon for SSD technology, especially since the cost of Flash memory in general continues to decrease at the rate of 40% to 50% per year.