Welcome!

SDN Journal Authors: Elizabeth White, Michael Thompson, Rachel A. Dines, Adrian Bridgwater, Michael Bushong

Related Topics: Virtualization, Java, SOA & WOA, Cloud Expo, Big Data Journal, SDN Journal

Virtualization: Article

SSD vs. HDD – The Battle for the Future of Storage

Look to the latest economically sensible storage solutions that are answering today’s performance and capacity calls

I have been working for technology companies for 33 years now, so I don't know why I'm always surprised at the technology myths that proliferate. For example, there is a popular notion running around that Solid State Drives (SSDs) will replace Hard Disk Drives (HDDs) as the dominant storage media. So, which will win? Let me give you my answer upfront before I take you through my arguments: both win, and the market size for both continues to grow.

As I offer up this data and this perspective, I'll repeat some advice I received early in my career. A mentor once told me, when searching for the truth in business and technology "look to the economics" (maybe my version of "go to the mattresses" for you "Godfather" fans).

Here is what I read and hear on a regular basis regarding the battle of HDDs and SSDs:

  • SSDs run circles around HDDs for performance
  • SSDs will soon replace HDDs
  • The improving density of SSDs will collapse the current cost premium to HDDs

Sound familiar? Well, as with most claims of this ilk, there are some elements of truth to them but each of these statements goes too far when viewed in light of some data.

Performance
Yes, it's true that SSDs are fundamentally faster than HDDs. This is particularly true of random I/O data reading (as with databases). With large block sequential data (i.e., rich media like video), however, this difference tends to be very small.

Replacing HDD?
Here's a claim where the data just doesn't add up. While the attractiveness of the SSD technology would lead one to believe this, the economics really don't hold up. I should probably point more specifically to NAND flash here (the "solid state" in SSDs) because another solid state technology might actually achieve this, but that appears to be years and tens of billions of dollars away.

Let's talk for a minute about the world's demand for storage. Last year approximately 2500 exabytes of data was created and/or replicated. And...this is doubling about every two years. This needs to be serviced largely by HDDs and SSDs. Last year, the NAND flash industry produced somewhere between 30 and 40 exabytes of storage; with somewhere around 3.5 exabytes finding its way into SSDs (the balance in phones, tablets, cameras, etc.). What is that, 1.4% of our total storage need? But production is ramping up... at a capital cost of about $1.5 billion per Exabyte (semiconductor fabs are expensive)! So, from an available supply perspective, SSDs replacing HDDs seems implausible.

Improving Technology Makes SSDs Cheaper
Agree. The NAND flash technology point is at 21nm line widths with plans to move to 19, then 16 nm. Storage density is further improving with the use of multi-level cell (MLC) capabilities vs single-level cell (SLC). This is bringing down the cost of solid state storage in much the same way the areal density increases seen in HDDs brought down the cost of hard drive storage.

Notice how I said "brought" down (i.e., past tense)? Because a real density growth in the hard drive industry has slowed to a crawl, the rapid erosion of cost/Gb has also slowed to a crawl. Now, the HDD industry needs to move to its next technology (HAMR?) to continue to take cost out and HAMR is a number of years away. HAMR will require significant capital investment by the HDD companies. Significant capital investment will be required anyway to keep up with storage demand (even more so with slowing areal density growth). This all spells out a flattening of HDD costs for the foreseeable future. Some would speculate that a renewed interest in improving the utilization of HDD capacity is an artifact of these economics.

Here's what's preventing the complete collapse of the price difference between the two technologies. The NAND flash suppliers have a similar problem as the HDD manufacturers... the implications of shrinking technology geometries. As the line widths shrink, the ability of flash to sustain multiple write-erase cycles declines. To make up for this deficiency, sophisticated error-correction algorithms and "brute force" overprovisioning (to allow some cells to wear out) are being used. This and the above mentioned semiconductor fab costs tend to mitigate the progress SSDs are making in closing the cost gap to HDDs.

Having made my arguments that SSDs won't take over the world, I have to say that IT solutions need this technology. I think you can see that SSDs aren't the answer to all our storage needs, but they allow us to address a crying storage requirement. At a high level, storage is called on to produce two key deliverables:

  • Make data available to an application or user in an appropriate timeframe (i.e., performance) and in today's environment this need is growing.
  • Store data reliably (i.e., capacity) and in today's environment this need is growing

By and large, to date, systems with hard drives have been architected to deliver both of these capabilities. It's hard to argue that hard drives haven't done a good job of delivering affordable capacity. But to deliver against the performance requirements of IT solutions, hard drives:

  • Have been developed with higher speeds, but arguably little progress has been made in the last ten years
  • Have been "short stroked" (a technique limiting the stroke of the actuator to improve performance)
  • Have been grouped together to allow striping of data across a large number of drives to aggregate their performance.

With each of these approaches the user suffers from higher power requirements, and with the last two approaches their system has been overprovisioned (leaving stranded capacity) to deliver performance. This all adds up to significant system cost that can be avoided with new storage architectures.

Here's where SSDs come in. SSDs are proving to be a technology answer to the new generation of storage needs, both the growing performance and the growing capacity requirements. Here's the simple, logical way to think about SSDs and HDDs and their role in storage solutions. Use the right tool for the job. That is, take advantage of SSDs for performance (particularly small block, random I/O) and HDDs for capacity.

You might challenge me now and ask, "Does adding SSDs (Flash) to IT solutions make economic sense?" SSDs are expensive, but, used appropriately, SSDs can also minimize the number of HDDs required in a given solution. The secret is in optimizing the use of both, that is, avoid overprovisioning of both. Thin provisioning of capacity has become popular as a cost saver. Similarly, thin provisioning of performance is a similar cost saver. (This is a benefit of virtualized caching or tiering capabilities of newer storage solutions.)

I'll close with a few proof points. Look to the latest economically sensible storage solutions that are answering today's performance and capacity calls. The vast majority of affordable "Ultrabooks" incorporate both flash and hard drive technology, as does Apple's latest "Fusion" drive.

More Stories By Tom Major

Tom Major is President of Starboard Storage. He joined Starboard from Seagate Technology, where he was senior vice president of Product Management and Business Operations. Before Seagate, Major worked at LeftHand Networks as chief strategy officer. Previous positions included vice president and general manager, Disk Business Unit, at StorageTek and vice president of Network Storage Marketing at HP, where he spent 21 years.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


Cloud Expo Breaking News
"We are automated capacity control software, which basically looks at all the supply and demand and running a virtual cloud environment and does a deep analysis of that and says where should things go," explained Andrew Hillier, Co-founder & CTO of CiRBA, in this SYS-CON.tv interview at the 14th International Cloud Expo®, held June 10-12, 2014, at the Javits Center in New York City. Cloud Expo® 2014 Silicon Valley, November 4–6, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading Cloud industry players in the world.
Almost everyone sees the potential of Internet of Things but how can businesses truly unlock that potential. The key will be in the ability to discover business insight in the midst of an ocean of Big Data generated from billions of embedded devices via Systems of Discover. Businesses will also need to ensure that they can sustain that insight by leveraging the cloud for global reach, scale and elasticity. In his session at Internet of @ThingsExpo, Mac Devine, Distinguished Engineer at IBM, will discuss bringing these three elements together via Systems of Discover.
All too many discussions about DevOps conclude that the solution is an all-purpose player: developer and operations guru, complete with pager for round-the-clock duty. For most organizations that is not the way forward. In his session at DevOps Summit, Bernard Golden, Vice President of Strategy at ActiveState, will discuss how to achieve the agility and speed of end-to-end automation without requiring an organization stocked with Supermen and Superwomen.
"In my session I spoke about enterprise cloud analytics and how we can leverage analytics as a service," explained Ajay Budhraja, CTO at the Department of Justice, in this SYS-CON.tv interview at the 14th International Cloud Expo®, held June 10-12, 2014, at the Javits Center in New York City. Cloud Expo® 2014 Silicon Valley, November 4–6, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading Cloud industry players in the world.
The Internet of Things promises to transform businesses (and lives), but navigating the business and technical path to success can be difficult to understand. In his session at 15th Internet of @ThingsExpo, Chad Jones, Vice President, Product Strategy of LogMeIn's Xively IoT Platform, will show you how to approach creating broadly successful connected customer solutions using real world business transformation studies including New England BioLabs and more.
“We are starting to see people move beyond the commodity cloud and enterprises need to start focusing on additional value added services in order to really drive their adoption," explained Jason Mondanaro, Director of Product Management at MetraTech, in this SYS-CON.tv interview at the 14th International Cloud Expo®, held June 10-12, 2014, at the Javits Center in New York City. Cloud Expo® 2014 Silicon Valley, November 4–6, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading Cloud industry players in the world.
There is no doubt that Big Data is here and getting bigger every day. Building a Big Data infrastructure today is no easy task. There are an enormous number of choices for database engines and technologies. To make things even more challenging, requirements are getting more sophisticated, and the standard paradigm of supporting historical analytics queries is often just one facet of what is needed. As Big Data growth continues, organizations are demanding real-time access to data, allowing immediate and actionable interpretation of events as they happen. Another aspect concerns how to deliver data in a meaningful way, one that really delivers on what end-users need to maintain a competitive position in fast-changing markets.
SYS-CON Events announced today that Gigaom Research has been named "Media Sponsor" of SYS-CON's 15th International Cloud Expo®, which will take place on November 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Ashar Baig, Research Director, Cloud, at Gigaom Research, will also lead a Power Panel on the topic "Choosing the Right Cloud Option." Gigaom Research provides timely, in-depth analysis of emerging technologies for individual and corporate subscribers. Gigaom Research's network of 200+ independent analysts provides new content daily that bridges the gap between breaking news and long-range research.
“The Internet of Things is a wave that has arrived and it’s growing really fast. The concern at Aria Systems is making sure that people understand the ramifications of their attempts to monetize whatever it is they build on the Internet of Things," explained C Brendan O’Brien, Co-founder and Chief Architect at Aria Systems, in this SYS-CON.tv interview at the Internet of @ThingsExpo, held June 10-12, 2014, at the Javits Center in New York City. Internet of @ThingsExpo 2014 Silicon Valley, November 4–6, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading IoT industry players in the world.
“About two years ago Brother launched a new group called Brother Online. We thought it was a good idea for a hardware company to get into the cloud services market and our first step into that market was web conferencing,” explained Courtney Behrens, Senior Marketing Manager at Brother International, in this SYS-CON.tv interview at the 14th International Cloud Expo®, held June 10-12, 2014, at the Javits Center in New York City. Cloud Expo® 2014 Silicon Valley, November 4–6, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading Cloud industry players in the world.
"So many teams have been stuck in their own practices for the last ten years and it's really hard to sell all the latest and greatest tools, but the reality is all the tools around operations have evolved so much you are starting to see a big shift toward upgrading that tool set, focusing more on automation, more on cloud," explained Dustin Whittle, Developer Evangelist at AppDynamics, in this SYS-CON.tv interview at the DevOps Summit, held June 10-12, 2014, at the Javits Center in New York City.
“We provide disaster recovery services as well as solutions. We also provide back-up solutions that work across your internal on-premise assets as well as in the public and private cloud," stated Joel Ferman, Vice President of Marketing at InMage Systems, in this SYS-CON.tv interview at the 14th International Cloud Expo® (http://www.CloudComputingExpo.com/), held June 10-12, 2014, at the Javits Center in New York City. Cloud Expo® 2014 Silicon Valley, November 4–6, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading Cloud industry players in the world.
SYS-CON Events announced today that Harbinger Systems will exhibit at SYS-CON's 15th International Cloud Expo®, which will take place on November 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA. Harbinger Systems is a global company providing software technology services. Since 1990, Harbinger has developed a strong customer base worldwide. Its customers include software product companies ranging from hi-tech start-ups in Silicon Valley to leading product companies in the US and large in-house IT organizations.
“Distrix fits into the overall cloud and IoT model around software-defined networking. There’s a broad category around software-defined networking that’s focused on data center, and we focus on the WAN,” explained Jay Friedman, President of Distrix, in this SYS-CON.tv interview at the Internet of @ThingsExpo, held June 10-12, 2014, at the Javits Center in New York City. Internet of @ThingsExpo 2014 Silicon Valley, November 4–6, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading IoT industry players in the world.
“Dell Cloud Manager is a cloud management environment for the consumption of cloud resources and we provide a consistent interface, both in terms of API and in terms of user interface for doing a wide variety of activities core to deploying and operating software in cloud," explained James Urquhart, Technologist & Director of Cloud Management Solutions at Dell, in this SYS-CON.tv interview at the 14th International Cloud Expo®, held June 10-12, 2014, at the Javits Center in New York City. Cloud Expo® 2014 Silicon Valley, November 4–6, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading Cloud industry players in the world.