Flash Data Storage: Myth vs. Reality

Posted on September 25, 2013 By Greg Schulz

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The interest in flash and SSD is huge – and so is the hype. So here’s the truth about some common nand flash SSD myths and realities to help you cut through the hype.

Feel free to add your perspectives in the Comment section below – and tell us about your favorite myth, fud and reality.

Myth: USB thumb drives are not SSD

Reality: That depends on your definition of what is or is not a SSD. On an enterprise storage system basis, a nand flash USB thumb drive is not on the level of that category of SSD solutions. However, for many other environments, a USB thumb drive is a SSD, just without all the feature, functionality and capabilities of a larger solution.

Myth: SSD are DRAM and not nand flash-based

Reality: This is a carry-over myth from those who first used DRAM based SSDs a few decades ago and now associated nand flash with USB thumb drives. The reality is that there are both DRAM and nand flash-based SSDs and even hybrid solutions that combine the two, not to mention Solid State Hybrid Disk that include DRAM, nand flash and a HDD.

Myth: You need software to leverage SSD

Reality: Some products, devices or solutions may require some software ranging from a driver, tiering or caching tool for management while others will be plug and play. For the plug and play type devices or systems, additional benefit can be derived from using value added software tools.

Myth: SSD is too expensive

Reality: One of the most common mistakes I see people make is looking at SSD in general on a cost per capacity basis vs. on a cost per activity basis.

Instead of looking at how much space capacity you get per cost, look at how much activity in terms of IOPs, bandwidth, files moved or accessed, work done or productivity enhanced per cost.

Doing so will show that for active environments where you can leverage the improved performance and lower response time, SSD will be less costly than many disk-based approaches. On the other hand, if you are not able to use or take advantage of that extra performance, then there may not be a benefit.

Myth: SSD only works in new systems or architectures

Reality: Some existing storage systems or appliances do a better job of taking advantage of supporting SSD vs. others. With some systems, there is more write optimization for performance as well as wear leveling to increase duty cycle, minimize program/erase (P/E) cycles vs. other solutions.

In some cases, I have seen where simply attaching an SSD to a vendor’s solution can have the same or lower performance vs. other vendors HDD-based solutions, yet for other products, there can be noticeable improvements.

Simply being able to support a SSD device (drive or card) is one thing, yet it’s another to be able to leverage it, integrate the device and optimize to coexist with RAID or other functions without introducing new problems. By the way, care to guess who wants the myth that SSD does not work with existing storage systems to exist?

Yes, the startups, particularly the all-SSD based ones. However, given that there are tens if not hundreds of PBytes of nand flash drives shipped, installed and in use with existing storage systems, I would say myth busted, with caveats of course.

Myth: Small IOs or IOPS are best for SSD?

Reality: For out of this world marketing metrics, the smaller the IOP the better. However, those may not be meaningful without context. On the other hand some SSD implementations are optimized for read or write bandwidth, thus not all solutions are the same.

Myth: Nand flash SSD are about to be replaced by PCM or MRAM or something new

Reality: In terms of talking about something new or different, sure, that is always the case. Some new things are in the labs or early qualification testing. However, also keep in mind that nand flash has yet to reach its full market potential in terms of industry deploy or customer adoption after over 20 years of existence as a technology. It’s safe to say that while there are new things to talk and get excited about, like the disk drive and other things, nand flash will be around for a while.



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