Design Article
Establishing industry endurance standards for solid-state storage
Alvin Cox, JEDEC JC-64.8 Chairman and Seagate Senior Staff Engineer
11/27/2010 3:47 AM EST
Standards arrive: JEDEC JESD218 and JESD219
JEDEC is the leading developer of standards for the solid-state industry. With over 3,000 participants from nearly 300 companies, various standards work is brought together under 50 JEDEC committees to meet the needs of every segment of the industry, manufacturers and consumers alike.
JEDEC JESD218 and JESD219 address the standards needed to distinguish between SSD endurance in both enterprise and client application classes. Enterprise and Client are the two fundamental classes which serve as the building blocks for present and future solid state standard development. Both standards documents are available to download here. These standards define specific requirements for each application class, describe a test methodology, and create an SSD Endurance Rating that provides a standard comparison for SSD endurance based on application class.
Enterprise and Client Classes Defined
Since workloads vary with storage depending on their application environment, Enterprise and Client class categories have different needs that must be met according to the standard. The Client class is derived from a single-drive environment, with an emphasis on notebook applications. The Enterprise class is based on a multi-drive environment, with an emphasis on random access and mixed workloads.
In addition to different daily usage and temperature environments, specific power-off long-term data retention and UBER (unrecoverable bit error rate) requirements must be met for each class.
The Enterprise class requires operation typical of a server in use 24 hours per day. The Client class reflects typical notebook active use of 8 hours per day.
Next: SSD Endurance Rating
JEDEC is the leading developer of standards for the solid-state industry. With over 3,000 participants from nearly 300 companies, various standards work is brought together under 50 JEDEC committees to meet the needs of every segment of the industry, manufacturers and consumers alike.
JEDEC JESD218 and JESD219 address the standards needed to distinguish between SSD endurance in both enterprise and client application classes. Enterprise and Client are the two fundamental classes which serve as the building blocks for present and future solid state standard development. Both standards documents are available to download here. These standards define specific requirements for each application class, describe a test methodology, and create an SSD Endurance Rating that provides a standard comparison for SSD endurance based on application class.
Enterprise and Client Classes Defined
Since workloads vary with storage depending on their application environment, Enterprise and Client class categories have different needs that must be met according to the standard. The Client class is derived from a single-drive environment, with an emphasis on notebook applications. The Enterprise class is based on a multi-drive environment, with an emphasis on random access and mixed workloads.
In addition to different daily usage and temperature environments, specific power-off long-term data retention and UBER (unrecoverable bit error rate) requirements must be met for each class.
The Enterprise class requires operation typical of a server in use 24 hours per day. The Client class reflects typical notebook active use of 8 hours per day.
Next: SSD Endurance Rating
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Robotics Developer
11/27/2010 10:42 PM EST
I like the idea of standards being promoted for SSDs! I do wonder what the failure mechanism is for SSDs, is it device failure related to MTBF or due to the exceeding the write over capacity of a section of memory rendering it non-operable? Once the cost of SSDs comes down I expect to see more adoption into the consumer market devices.
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goafrit
11/29/2010 12:20 AM EST
I agree with you. The key aspect is the cost. It must come down to help spur adoption across different platforms.
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DSzabados
12/1/2010 1:21 PM EST
Regarding the failure mechanisms, the most common are shipping damage, random component infant mortality, and assembly defects. Such failures are not due to the endurance of the memory components. Regarding endurance, there are definitely two classes of SSDs. The workloads for enterprise and client are extremely different and an SSD that is not specifically designed to deal with the demands of the enterprise workload could be at risk of endurance (memory) failure if used in an enterprise application. From a client perspective, any properly designed SSD should provide many years of dependable service. In the enterprise application, be sure to get an enterprise SSD.
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Charles.Desassure
11/30/2010 7:08 PM EST
Thanks for this article. Standards are always good as it relates to technology. I strongly support and agree with this article. As someone mentioned before, cost is a key factor.
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Duane Benson
12/1/2010 1:43 PM EST
Certainly standards are important, but I don't think that the lack of these standards is a first order, or even a second order factor in the limited level of adoption. I can buy a Terrabyte spinning media HD for $60.00. The cheapest SSD I found (in my three minute research project) was $60.00 for a 4GB device. On the same site, I found a 128GB SSD ranging in price from $239 to $469.
That's more than 30 times the cost per byte at best. When the SSDs are in the range of two or three times the cost per byte, then things like standards start to be a part of the decision making process.
There are applications with very specific requirements that override the 30X cost factor, but I really doubt that standards, again, factor in to those decision.
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