By Kevin Komiega
-- The recent buzz surrounding flash-based storage and its potential applications in the enterprise has prompted many in the industry to weigh the pros and cons of augmenting or replacing traditional hard disk drives (HDDs) with high-performance solid-state disk (SSD) drives in the data center.
The increased interest in SSDs has also prompted research firm IDC to ramp up its coverage of the market and has resulted in a new benchmarking study in which IDC compared SSDs, HDDs, and hybrid HDDs (H-HDDs) to gauge the real-world I/O performance differences between the three technologies.
Though the study, "Benchmarking Storage Options for PCs: The Results Are In - Exposing the Strengths and Weaknesses of HDDs, SSDs, and Hybrids," is primarily focused on drive technologies for desktops and laptops, some of its conclusions can be applied to enterprise storage environments.
David Reinsel, group vice president for storage and semiconductors research at IDC, says some results were predictable while others were unexpected.
IDC assumed at the outset that SSDs would outperform HDDs or hybrid drives by a healthy margin, regardless of the test configuration, but some of the results surprised him. "Hard drives have been plug-and-play in the PC environment for a long time. You can take a drive from any disk manufacturer and expect good, predictable performance. However, when you put in an SSD, which is essentially a turbocharger, you should not necessarily expect the same results."
Reinsel says SSDs generally outperformed HDDs and H-HDDs, but there are bigger issues at play than I/Os per second (IOPS). Namely, the impact that overall system design has on the performance of SSDs.
He says designers need to design systems to take advantage of SSDs. Reinsel believes an "intelligent redesign" of enterprise storage arrays is in order.
According to the study, the key to the success of SSD technology for enterprise applications depends on the controller. Reinsel says storage controller technologies with the ability to manage the NAND memory efficiently will be one of the key differentiators among vendors of single-level cell (SLC) and multi-level-cell (MLC) flash-based SSDs.
Reinsel also says the process of building new enterprise storage arrays capable of taking full advantage of SSDs will be slow and deliberate. "There are products available today and we will see that number increase over time, but they will probably not be available and adopted en masse until 2010," he says.
Another recent IDC research study, "Worldwide Solid State Drive 2007-2012 Forecast and Analysis: Entering the No-Spin Zone," shows the worldwide SSD market generated nearly $400 million in revenues in 2007. IDC predicts SSD revenue will increase at a 70% compound annual growth rate (CAGR) from 2007–2012 and unit shipments at a slightly faster rate of 76%.
How much of that growth will be attributed to enterprise storage remains unclear. What is clear is that early adopters will be companies that can afford the SSD premium.
"People want to do it and there are a lot of promises out there, but in reality I don't think all of the [storage vendors] have the tools in place to do it effectively at this point," says Reinsel. "There are certain parts of the industry where IOPS mean everything such as Wall Street transactions, real-time airline reservations -- anywhere that more transactions mean more dollars."
"People will start adopting SSDs in the enterprise when they see value in performance improvements. Right now they are paying a large premium and if the systems don't perform as users expect there will be some level of disappointment," Reinsel says.
According to IDC, the test results indicate that traditional HDD technology is going to be around for years to come. However, H-HDD and SSD technologies will experience increased adoption rates as price points decline, technology improves, and use cases evolve.