Click here to close now.

Welcome!

SDN Journal Authors: Pat Romanski, Liz McMillan, Yeshim Deniz, Carmen Gonzalez, Elizabeth White

Related Topics: Virtualization, Java, Microservices Journal, 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.


@CloudExpo Stories
Want to enable self-service provisioning of application environments in minutes that mirror production? Can you automatically provide rich data with code-level detail back to the developers when issues occur in production? In his session at DevOps Summit, David Tesar, Microsoft Technical Evangelist on Microsoft Azure and DevOps, will discuss how to accomplish this and more utilizing technologies such as Microsoft Azure, Visual Studio online, and Application Insights in this demo-heavy session.
DevOps Summit, taking place Nov 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 17th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long developmen...
The 5th International DevOps Summit, co-located with 17th International Cloud Expo – being held November 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA – announces that its Call for Papers is open. Born out of proven success in agile development, cloud computing, and process automation, DevOps is a macro trend you cannot afford to miss. From showcase success stories from early adopters and web-scale businesses, DevOps is expanding to organizations of all sizes, including the...
SYS-CON Events announced today that MetraTech, now part of Ericsson, has been named “Silver Sponsor” of SYS-CON's 16th International Cloud Expo®, which will take place on June 9–11, 2015, at the Javits Center in New York, NY. Ericsson is the driving force behind the Networked Society- a world leader in communications infrastructure, software and services. Some 40% of the world’s mobile traffic runs through networks Ericsson has supplied, serving more than 2.5 billion subscribers.
Over the years, a variety of methodologies have emerged in order to overcome the challenges related to project constraints. The successful use of each methodology seems highly context-dependent. However, communication seems to be the common denominator of the many challenges that project management methodologies intend to resolve. In this respect, Information and Communication Technologies (ICTs) can be viewed as powerful tools for managing projects. Few research papers have focused on the way...
As the world moves from DevOps to NoOps, application deployment to the cloud ought to become a lot simpler. However, applications have been architected with a much tighter coupling than it needs to be which makes deployment in different environments and migration between them harder. The microservices architecture, which is the basis of many new age distributed systems such as OpenStack, Netflix and so on is at the heart of CloudFoundry – a complete developer-oriented Platform as a Service (PaaS...
As cloud gives an opportunity to businesses to buy services externally – how is cloud impacting your customers? In his General Session at 15th Cloud Expo, Fabio Gori, Director of Worldwide Cloud Marketing at Cisco, provided answers to big questions: Do you see hybrid cloud as where the world is going? What benefits does it bring? And how does Cisco connect all of these clouds? He also discussed Intercloud and Cisco’s investment on it.
17th Cloud Expo, taking place Nov 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy. Meanwhile, 94% of enterprises a...
The 17th International Cloud Expo has announced that its Call for Papers is open. 17th International Cloud Expo, to be held November 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, APM, APIs, Microservices, Security, Big Data, Internet of Things, DevOps and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding bu...
There is no question that the cloud is where businesses want to host data. Until recently hypervisor virtualization was the most widely used method in cloud computing. Recently virtual containers have been gaining in popularity, and for good reason. In the debate between virtual machines and containers, the latter have been seen as the new kid on the block – and like other emerging technology have had some initial shortcomings. However, the container space has evolved drastically since coming on...
The Internet of Things is not new. Historically, smart businesses have used its basic concept of leveraging data to drive better decision making and have capitalized on those insights to realize additional revenue opportunities. So, what has changed to make the Internet of Things one of the hottest topics in tech? In his session at @ThingsExpo, Chris Gray, Director, Embedded and Internet of Things, discussed the underlying factors that are driving the economics of intelligent systems. Discover ...
Enterprises are fast realizing the importance of integrating SaaS/Cloud applications, API and on-premises data and processes, to unleash hidden value. This webinar explores how managers can use a Microservice-centric approach to aggressively tackle the unexpected new integration challenges posed by proliferation of cloud, mobile, social and big data projects. Industry analyst and SOA expert Jason Bloomberg will strip away the hype from microservices, and clearly identify their advantages and d...
With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo in Silicon Valley. Learn what is going on, contribute to the discussions, and ensure that your enterprise is as "IoT-Ready" as it can be! Internet of @ThingsExpo, taking place Nov 3-5, 2015, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 17th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading in...
The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long development cycles that produce software that is obsolete at launch. DevOps may be disruptive, but it is essential. The DevOps Summit at Cloud Expo – to be held June 3-5, 2015, at the Javits Center in New York City – will expand the DevOps community, enable a wide...
In her General Session at 15th Cloud Expo, Anne Plese, Senior Consultant, Cloud Product Marketing, at Verizon Enterprise, focused on finding the right mix of renting vs. buying Oracle capacity to scale to meet business demands, and offer validated Oracle database TCO models for Oracle development and testing environments. Anne Plese is a marketing and technology enthusiast/realist with over 19+ years in high tech. At Verizon Enterprise, she focuses on driving growth for the Verizon Cloud platfo...
Cloud Expo, Inc. has announced today that Andi Mann returns to DevOps Summit 2015 as Conference Chair. The 4th International DevOps Summit will take place on June 9-11, 2015, at the Javits Center in New York City. "DevOps is set to be one of the most profound disruptions to hit IT in decades," said Andi Mann. "It is a natural extension of cloud computing, and I have seen both firsthand and in independent research the fantastic results DevOps delivers. So I am excited to help the great team at ...
How does one bridge the gap between traditional enterprise storage infrastructures and the private, hybrid, and public cloud? In his session at 15th Cloud Expo, Dan Pollack, Chief Architect of Storage Operations at AOL Inc., examed the workload differences and required changes to reuse existing knowledge and components when building and using a cloud infrastructure. He also looked into the operational considerations, tool requirements, and behavioral changes required for private cloud storage s...
Software is eating the world. Companies that were not previously in the technology space now find themselves competing with Google and Amazon on speed of innovation. As the innovation cycle accelerates, companies must embrace rapid and constant change to both applications and their infrastructure, and find a way to deliver speed and agility of development without sacrificing reliability or efficiency of operations. In her Day 2 Keynote DevOps Summit, Victoria Livschitz, CEO of Qubell, discussed...
The time is ripe for high speed resilient software defined storage solutions with unlimited scalability. ISS has been working with the leading open source projects and developed a commercial high performance solution that is able to grow forever without performance limitations. In his session at DevOps Summit, Alex Gorbachev, President of Intelligent Systems Services Inc., will share foundation principles of Ceph architecture, as well as the design to deliver this storage to traditional SAN st...
Gartner predicts that the bulk of new IT spending by 2016 will be for cloud platforms and applications and that nearly half of large enterprises will have cloud deployments by the end of 2017. The benefits of the cloud may be clear for applications that can tolerate brief periods of downtime, but for critical applications like SQL Server, Oracle and SAP, companies need a strategy for HA and DR protection. While traditional SAN-based clusters are not possible in these environments, SANless cluste...