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 In the data center storage arena, many innovations in recent years have targeted storage management, but a new type of drive is set to usher in changes that could impact storage across the board. The SSD, or solid-state drive, is building momentum within the IT space, with manufacturers increasingly offering it as an option alongside conventional hard drives.
Generally using either NAND flash nonvolatile memory or DRAM volatile memory, SSDs deliver a wealth of benefits over drives that employ older technology. “Greater reliability in SSDs means longer drive life with fewer replacements,” says Terrence Groth, product marketing manager for SSD products at Lexar Media’s Crucial division (www.crucial.com). “With no moving parts, the power/cost savings ratio can be significant as you begin adding multiple drives per server to your data center. With SSD technology, information flow is faster with low latency and high read/write speeds.”
Indeed, SSDs feature extremely quick startup times, fast random access, excellent mechanical reliability, and no noise, thanks to the lack of moving parts. However, as costs remain high and other questions surround the technology, integration into data centers isn’t exactly occurring at a breakneck pace.
 Performance Aplenty
Currently and in the near future, SSDs could impact specific data center realms—particularly those demanding plenty of performance. Brian Beard, SSD market team leader for Samsung Semiconductor (www.samsung.com), says these realms will include Web servers and OLTP (online transaction processing), which currently use 15,000rpm hard disk drives that are “short stroked,” or use only the outmost diameter of the drive to optimize performance.
For these performance-focused applications, Beard says a single SSD could replace several short-stroked HDDs. Further, he notes that SSDs use only 0.5 watts of power, far less than the 10 to 15W used by server HDDS. “Besides huge gains in performance and power/cooling costs, ultimately SSDs could allow SMBs to reduce the number of total servers required, thus reducing overall costs, or they may enable more SMBs to take advantage of cloud computing, utilizing outsourced server capacity to reduce the need for a high [capital expenditure] on IT infrastructure,” he says.
Performance certainly drives uptake for other hardware, and some experts say they believe the impressive I/O performance of SSDs—at least in some usage cases—will be welcomed by IT professionals. “I/O is one of the more difficult aspects to storage management, namely because end users often have no meaningful way to translate what they do to I/O operation metrics within a storage subsystem,” says Steve Merkel, CIO at Data393 (www.data393.com), a managed hosting and colocation facility in Denver. “So having I/O to spare will make capacity planning around storage a bit easier.”
Not Quite Perfection
According to Sherman Black, senior vice president and general manager of Seagate’s Enterprise Compute division (www.seagate.com), SSDs are an option—an expensive option—for only the largest data centers, while their costs will likely prohibit widespread adoption in SMEs. Further, future integration of SSDs into data centers will depend on suppliers doing a better job of describing their products and the development of standards.
“Today, there is considerable confusion in the marketplace on descriptions of performance and endurance of SSDs, creating situations where the wrong product was used in an application and ultimately does not meet the needs and expectations of the end user. There are many technologies that can be used to create SSDs, including MLC [multilevel cell] and SLC [single-level cell], and each has different performance and reliability characteristics,” Black says.
He adds that the SSD industry needs a more concerted effort to define best-fit applications for SSDs, such as enterprise vs. notebook, so that IT architects can make better-informed decisions. Another potential drawback is that elements of SSD performance vary from other storage technologies, but not always for the better. Merkel says that depending on the implementation, SSDs could have slower write performance than conventional storage devices.
“Some SSDs are rated for fewer write cycles than other technologies. Consequently, SSDs may not make sense if the application has an I/O profile that contains large percentages of small writes. It is important for technologists to understand the environment and understand how changing storage methodologies impacts their application performance and reliability,” Merkel says.
Eye Toward The Future
SMEs willing to assume the role of early adopter will discover that SSDs are not difficult to integrate into an existing storage architecture. Samsung’s Beard says that while some SSDs offer SAS and Fibre Channel connections, the industry is leaning more toward SATA connections. For example, Samsung offers 2.5-inch SATA drives that can integrate into any environment that accommodates SATA drives.
However, while IT professionals won’t need to revamp existing hardware or software to accommodate SSDs, the technology could bring future challenges. “There are some unique characteristics of an SSD requiring extensions to existing interface standards,” Seagate’s Black says. “For example, the NAND flash used in SSDs eventually will wear out. In this example, extensions are needed to the existing interface standards to provide gas gauge-like reporting functionality so that SSDs can be replaced before they reach the end of their useful life.”
Although Merkel has yet to see any impact from SSDs within the data center space—primarily because adoption rates are low at the server or large storage arrays level—he acknowledges the technology holds promise. “Clearly we are excited about the technology and what it could bring—namely, reduced power consumption and increased I/O performance,” he says. “However, until we start to see production deployments of the technology on any real scale, the impact will be theoretical.” 
by Christian Perry
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