What is SSD storage? Answers to common solid-state storage questions

Looking for better knowledge about SSD storage? Check out Dennis Martin’s answers to common solid-state storage questions.

If you are new to solid-state storage, our Ask the Expert section is a great place to learn more. Below you will...

find a short primer to get you started.

Whether it’s differentiating between solid state drives (SSD) and hard disk drives (HDD), discussing the cost of an SSD as compared to a traditional hard drive, explaining the difference between SLC and MLC SSDs, or looking at NAND flash reliability, these answers will help you understand the basics of solid-state storage a bit better.

Also, Dennis Martin, the founder and president of Demartek, a computer industry analyst organization with its own on-site test lab, is available to answer any SSD questions you might have. Just click on the “Ask a Question” tab on his bio page.

In the meantime, here are some of Dennis’ answers to common solid-state storage questions.

SSD vs. hard disk drive

Though they are available in the same form factors as typical hard drives, SSDs are quite different in construction and function. The physical differences between SSDs and HDDs are outlined in this answer.

SSD cost vs. traditional hard drives

Cost has always been the number one factor preventing storage administrators from deploying SSDs. The gap between SSD and HDD pricing has narrowed over the past few years. The cost of SSDs and HDDs are compared in this answer.


There are a variety of choices available when choosing an SSD depending on the use case. This answer details the differences between SLC and MLC SSDs, and explains the different levels of MLC SSDs.

Long term MLC SSD reliability

Concerns about the long-term reliability of MLC SSDs have prevented many storage administrators from deploying solid state storage. This answer details what you should know about the reliability of MLC SSDs over time

Sub-volume automated tiering does trigger added work

Sub-volume automated tiering requires additional work to be performed by the storage system, whether SSDs or HDDs are involved. This answer describes the process and performance impact.

Primary storage deduplication and SSDs

As noted above, cost is a big factor to consider before deploying SSDs. This answer discusses whether primary storage deduplication would bring the price of SSDs closer to HDD pricing.

NAND flash reliability: Concerns with process geometry

As NAND flash process geometry has scaled down from more than 50 nanometers to about 20nm, the endurance and performance have gotten worse. NAND flash reliability concerns associated with process geometry are detailed in this answer.

How 3D NAND flash works and why it is important

3D NAND flash is a new type of flash memory that stacks cells vertically, providing considerably more electrons in the same form factor. This answer details how 3D NAND flash works and why it is important.

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