Debunking SSD myths

Despite the huge gains that solid-state drives are making, some myths persist -- all unjustified

 By now everyone is aware of the performance leap offered by solid-state drives (SSDs) compared to hard disk drives (HDDs), but some SSD myths persist. It’s time to separate fact from fiction.

Myth 1: SSDs are prohibitively expensive

An SSD can cost more than its HDD equivalent when you look simply at the price tag for a given capacity. However, cost savings can be seen when you look at the amount of real-world performance each of your dollars buys. For example, one SSD can do the work of about 40 HDDs, but that SSD doesn’t cost 40 times as much. In fact, an SSD costs less when you consider the work it accomplishes.

This metric is best expressed as dollar per input/output operations per second (IOPS, pronounced eye-ops). This performance-based measurement provides a more complete picture on the performance you’re able to get out of an SSD. The cost per IOPS is less than $0.10 for an SSD compared to more than $1.40 for an HDD.


15.01.23 ssd graphic

There are other cost benefits to consider as well. The first is energy consumption. SSDs consume less power than HDDs. Since far fewer SSDs are required than HDDs to deliver equivalent performance, the power-sipping SSDs use far less combined system power than HDDs. For example, a modern data center SSD uses just 5 watts – the equivalent power used by a dim nightlight bulb – and these 5 watts can deliver some 75,000 IOPS of performance.

The more IOPS, the faster tasks can be completed – everything from running games more smoothly to mapping proteins to help find a cure for cancer.

And because SSDs consume less power, they require fewer resources to cool them, as well as space to house them. Because you need fewer SSDs to complete the work of HDDs, you’re able to save valuable real estate in your data center. You can replace a rack of 500 HDDs with just a dozen SSDs, saving on space and limiting the total number of drives you need to purchase. That can deliver a 76% total hardware cost reduction on top of a 99% reduction in power needs (both to power the drives and to cool the servers) and a 95% space savings.

Imagine getting the performance from a single SSD that would require the money, power, cooling resources and space as more than 40 HDDs. Which technology is looking expensive now?

Myth 2: SSDs aren’t secure

The reality is quite the opposite: SSDs offer very advanced security for your most valuable data without compromising performance.

Many SSDs today are self-encrypting and offer enhanced security features such as hardware-based AES 256-bit encryption. AES, or advanced encryption standard, is an internationally recognized specification for the encryption of data established by the U.S. National Institute of Standards and Technology. It is the gold standard for data encryption today. So much so that AES has been adopted by the U.S. federal government as well as by some of the most data-demanding intelligence organizations around the world.

Hardware-based encryption means data is automatically encrypted and decrypted through an AES chip built directly on the SSD. This is much more secure and efficient than software-based encryption, where data is encrypted and decrypted via a software program on the PC and exposed to snooping of sensitive data.

Myth 3: SSDs aren’t reliable

Drive failures are a cost burden to consumers and IT departments. An HDD failing can lead to multiple hours of downtime and lost productivity and additional hours of work for IT to rebuild drives. When it happens to a personal computer it can have an even bigger impact – lost memories, money spent on trying to recover them, and time waiting for recovery software from the manufacturer.

Today’s SSDs undergo extensive quality testing and are engineered to reduce such costs and minimize downtime as a result of storage-related failures. One universally accepted metric for measuring SSD reliability is known as an “annual failure rate.” Exhaustive studies have shown that SSDs have an annual failure rate of tenths of one percent, while the AFRs for HDDs can run as high as 4 to 6 percent.

Additionally, unlike HDDs with their spinning disks, SSDs have no moving parts. As such, they are able to withstand shocks and vibrations without the risk of data loss. This feature has made SSDs a critical component in today’s increasingly mobile world. SSDs are found in myriad devices that have become integral parts of our on-the-go world: tablets, 2-in-1s and laptops.

This high reliability means SSDs provide consistence performance. The health of SSDs can be monitored and planned for. It’s this predictable reliability and the absence of mechanical parts that give SSDs a huge advantage over the unpredictable performance and high failure rate of HDDs.

Myth 4: SSDs lack endurance

Contrary to how some people think, the life of an SSD is measured not by time but in the number of writes. “Writes” is in reference to data being added – or written onto – a drive.

But first a little insight on how data is stored on an SSD. Think of an SSD as being divided into billions of cells that hold information. Before new data is added to a cell, any old data in that cell must first be removed. In this process, each cell is able to withstand only a certain number of erasures before that cell becomes unusable.

For example, some SSDs are designed to accommodate 10 drive writes per day consistently. At first glance this doesn’t sound like very much. But this metric means every single cell on the drive can handle 10 writes per day over a five-year life of the drive.

And since SSDs contain billions of cells, we’re talking about an enormous amount of data that can be written and deleted at every moment of every day of the drive’s life. For example, one 100GB SSD that offers 10 drive writes per day can support 1TB (terabyte) of writing each and every single day, 365 days a year for five years.

To put that in perspective, 1TB of data is equivalent to 1,000 copies of the Encyclopedia Britannica or as many as 200,000 MP3 files. And 10TB of writes would cover the entire printed collection of the U.S. Library of Congress.

Over a five-year period, this is more than 1.8PB (petabytes) of data writes. For context, 20 million file cabinets filled with text hold about 1PB of data, and all the photos on Facebook (about 10 billion) equal 1.5PB, give or take. We’re talking a truly massive amount of data here.

Brown is the SSD business development manager of Intel’s Non-Volatile Memory (NVM) Solutions Group. He advises leading IT decision makers on best practices around storage technologies. He served as SSD product line manager and is accredited with the development of multiple products and holds nine U.S. patents on NVM technology.

This story, "Debunking SSD myths" was originally published by Network World.

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