The Pros and Cons of SSD

By Pam Baker

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Editor's Note: See the updated version of this article to get the latest on SSD in the enterprise.

Solid state disks (SSD) made a splash in consumer technology, now the technology looks set to dominate the enterprise storage market. “Get ready for a disruption in the storage ecosystem,” said Burton Group Analyst Gene Ruth. Given the overwhelming challenges IT faces today, is that predicted disruption coming soon or will it merely end up on hold?

HP agrees with industry insiders that SSD will be more widely used in storage systems as early as next year and as a result, is working closely with its partners now to deliver innovative solid state storage technology solutions,” said Jieming Zhu, distinguished technologist at HP StorageWorks.

To SSD or Not to SSD

The storage industry has been trapped within the confines of a hard disk drive so long that it’s difficult for it to think out of that box,” said Ruth. “SSD technologies are game changing and drive a whole new thought pattern around persistent storage.”

Ultimately, SSDs challenge the infrastructure all around them. “Traditional RAID may not apply, busses are too slow, driver stacks have too much latency, file systems don’t properly leverage them, form factors don’t apply, performance is not linear, and on and on … it’s a brave new world. We’ll have to see how vendors choose to live in it,” said Ruth.

Storage vendors are all struggling with how to implement around SSDs – “whether to take baby steps or big leaps.” Whatever they decide, we should see some interesting new products this year. One key question remains center of the discussion: will vendors charge a premium for SSD performance and enhanced functionality or will they pass on savings and establish a new performance vs. cost expectation? “I hope they price in the savings,” said Ruth. Unit pricing will not be the only consideration, however.

Solid-state drives offer 50 to 100x performance improvement in certain applications and specifications over traditional hard disk drives,” said Troy Winslow, director of marketing at Intel NAND Solutions Group. “This performance improvement, particularly read and write input operations per second (IOPS), combined with lower power consumption in both idle and active states, means solid-state drives deliver greater performance and consume less power than traditional storage.”

Thus total cost impact is likely to take precedence over unit costs. “The decision to purchase SSD is almost always driven by a compelling return on investment (ROI),” said Ron Lloyd, product marketing manager at EMC Corp. “The combination of SSD technology, SATA technology, and advanced quality of service software features has changed how customers evaluate and plan their storage investments.”

Pros ...

Energy efficient. “Using SSD technology reduces the overall power consumption of devices such as disk arrays, servers and laptops, but also improves their performance and environmental ruggedness,” said HP’s Zhu.

Low latency. SSDs implemented for use as physical disk space allow users to automatically migrate active blocks of data between drive types, increasing performance by keeping frequently accessed blocks of data on “Tier 0” SSD storage, and dynamically moves inactive data to less expensive, lower tiers of storage. “By combining automated tiered storage feature sets with SSDs, end-users have the ability to purchase only the number of drives required to house active blocks of data, where other vendors require the costly purchase for entire volumes,” said Bob Fine, director of Product Marketing at Compellent .

It creates a Tier 0 storage environment and we will see a Tier 0 to Tier 2 storage infrastructure in the near future,” predicts Russ Johnson, senior vice president and general manager of AMCC's Storage Business Unit. AMCC is working with SSD companies to ensure its RAID controllers take advantage of SSD, allowing a mix of drive types without performance impacts. “We believe that 2009 will be the year that SSD finds it home."

Durability. “SSD is designed to operate in more extreme environments of up to 70 degrees Celsius. With no moving parts, SSD drives are less fragile and silent than hard disks, which are more susceptible to operational and non-operational shock and vibration,” explains Zhu.

Control of unstructured files. The incredible rise of unstructured data is having a dramatic impact on storage and data management applications. “We’re seeing growing demand for specialized storage systems, including storage media that give users the control or flexibility they need to manage unstructured files over their lifetime,” said Jon Affeld, senior director of Product Marketing and Business Development at BlueArc, a provider of high performance, unified network storage systems. “In the near term it will serve as a powerful caching tier for fast access to files that are in high demand. Moving forward, we can expect the use of SSDs to get more sophisticated as we see data management applications incorporating more powerful search, classification, archiving and retrieval functions.”

Compatibility with operating systems “All SSD vendors provide existing input/output storage protocol compatibility, interoperable with the existing operating system storage stack,” said Zhu.

Commoditized components. This is a classic “Adam Smithian market evolution” said CTO and Inventor of Fusion-io’s solution, David Flynn. What used to be a single, vertically integrated provider becomes a layered market where some people build the components, others integrate them (with some bit of value added), and the market moves to include many players competing on many levels, resulting in price reductions. “I’m not saying this market transformation is going to happen by tomorrow,” said Flynn. “But, given the geometric growth of the performance gap between processors and storage, and the geometric decline in cost of NAND flash - leading to a ‘Moore’s Law Squared’ effect in the benefit to cost ratio - it is going to happen faster than people would think.”

Cons …

Questionable life expectancy of SSD “NAND Flash, the underlying technology of today’s majority SSD products, has write wear-out limitations, with embedded processors, software and over provisioning of capacity, among other things,” said Zhu. SSD manufactures have addressed this limitation, however, this inevitably adds another link in the chain of the overall reliability of SSD-based systems that must be rigorously tested and certified. “The lack of standard measurement of the life expectancy of SSD is a major drawback,” Zhu warns.

SSD technology is nascent. HP and other industry leaders including Intel and Sun do not predict that SSD will replace hard drives in the enterprise. “Like any new technology, SSD is still at the testing stages so there are a number of factors and challenges that need to be addressed before it matures in the enterprise space,” said Zhu.

Not ideal for all. “SSD is not recommended for everyone, it is ideally suited for businesses that require high-performance, intensive I/O operations; are power sensitive; and/or are in a rugged environment,” said Zhu. HP expects SSD to be used as a premium performance tier in well balanced storage deployments.

More Expensive. “SSDs are a bit more expensive, have less capacity and a finite number of write cycles when compared to traditional spinning drives, but those drawbacks are quickly disappearing,” explains Charles Kaplan, chief technology strategist at Mazu Networks, now part of Riverbed, a wide area network (WAN) optimization solutions provider.

All things considered, CIOs are left guessing as to when precisely to make the jump. “In the enterprise, the benefits over traditional disk drives -- speed, reliability, efficiency, lower power consumption -- make SSDs a major disruptor in the storage space,” said Michael Cornwell, lead technologist for Flash Memory at Sun Microsystems. “However key players are only just beginning to recognize the market opportunity this technology has to offer.”