The Many Faces of Solid State Devices/Disks (SSD)

January 27, 2008 – 12:20 pm

Storage I/O trends

Here’s a link to a recent article I wrote for Enterprise Storage Forum titled “Not a Flash in the PAN” providing a synopsis of the many faces, implementations and forms of SSD based technologies that includes several links to other related content.

A popular topic over the past year or so has been SSD with FLASH based storage for laptops, also sometimes referred to as hybrid disk drives along with announcements late last year by companies such as Texas Memory Systems (TMS) of a FLASH based storage system combining DRAM for high speed cache in their RAMSAN-500 and more recently EMC adding support for FLASH based SSD devices in their DMX4 systems as a tier-0 to co-exist with other tier-1 (fast FC) and tier-2 (SATA) drives.

Solid State Disks/Devices (SSD) or memory based storage mediums have been around for decades, they continue to evolve using different types of memory ranging from volatile dynamic random access (DRAM) memory to persistent or non-volatile RAM (NVRAM) and various derivatives of NAND FLASH among other users. Likewise, the capacity cost points, performance, reliability, packaging, interfaces and power consumption all continue to improve.

SSD in general, is a technology that has been miss-understood over the decades particularly when simply compared on a cost per capacity (e.g. dollar per GByte) basis which is an unfair comparison. The more approaches comparison is to look at how much work or amount of activity for example transactions per second, NFS operations per second, IOPS or email messages that can be processed in a given amount of time and then comparing the amount of power and number of devices to achieve a desired level of performance. Granted SSD and in particular DRAM based systems cost more on a GByte or TByte basis than magnetic hard disk drives however it also requires more HDDs and controllers to achieve the same level of performance not to mention requiring more power and cooling than compared to a typical SSD based device.

The many faces of SSD range from low cost consumer grade products based on consumer FLASH products to high performance DRAM based caches and devices for enterprise storage applications. Over the past year or so, SSD have re-emerged for those who are familiar with the technology, and emerged or appeared for those new to the various implementations and technologies leading to another up swinging in the historic up and down cycles of SSD adoption and technology evolution in the industry.

This time around, a few things are different and I believe that SSD in general, that is, the many difference faces of SSD will have staying power and not fade away into the shadows only to re-emerge a few years later as has been the case in the past.

The reason I have this opinion is based on two basic premises which are economics and ecological”. Given the focus on reducing or containing costs, doing more with what you have and environmental or ecological awareness in the race to green the data center and green storage, improving on the economics with more energy efficiency storage, that is, enabling your storage to do more work with less energy as opposed to avoiding energy consumption, has the by product of improved economics (cost savings and improved resource utilization and better service delivery) along with ecological (better use of energy or less use of energy).

Current implementations of SSD based solutions are addressing both the energy efficiency topics to enable better energy efficiency ranging from maximizing battery life to boosting performance while drawing less power. Consequently we are now seeing SSD in general are not only being used for boosting performance, also we are seeing it as one of many different tools to address power, cooling, floor space and environmental or green storage issues.

Here’s a link to a StorageIO industry trends and perspectives white paper at

Here’s the bottom line, there are many faces to SSD. SSD (FLASH or DRAM) based solutions and devices have a place in a tiered storage environment as a Tier-0 or as an alternative in some laptop or other servers where appropriate. SSD compliments other technologies and SSD benefits from being paired with other technologies including high performance storage for tier-1 and near-line or tier-2 storage implementing intelligent power management (IPM).

Cheers gs

Greg Schulz – Author Cloud and Virtual Data Storage Networking (CRC Press, 2011), The Green and Virtual Data Center (CRC Press, 2009), and Resilient Storage Networks (Elsevier, 2004)

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