Although solid-state drives (SSDs) have been around for over a decade and hit mass market several years ago, manufacturers offered different metrics of their performance and reliability. As a result, it is hardly possible to compare different SSDs based on their specs. But this situation is coming to the end as JEDEC publishes the first standards for SSDs.
JEDEC, a leading standard setting organization, has announced the publication of two widely anticipated standards for SSDs: Requirements and Endurance Test Method (JESD218) and Endurance Workloads (JESD219). Interestingly, but the committee that sets the SSD standards is chaired by a senior engineer of Seagate Technology, one of the world's largest makers of hard disk drives which only recently started to offer SSDs.
“To achieve the goal of consensus-based industry standards for SSDs, JEDEC’s JC-64.8 subcommittee for solid state drives has taken the lead to provide meaningful, real-life, endurance and reliability metrics to better enable customers to select the right SSD for their expected applications and workloads. In developing these standards, JC-64.8 collaborated with numerous other industry groups and standards associations,” said Alvin Cox, Chairman JC-64.8 and senior engineer at Seagate Technology.
For each class of SSDs defined in the standard, JESD218 defines conditions of use and corresponding endurance verification requirements. As SSDs are subject to different levels of demand depending on the applications in use, the standard defines two application classes: Client and Enterprise. It further establishes specific requirements for each, an approach intended to help consumers and enterprise IT managers choose products that are the best fit for their needs.
Endurance Rating and Verification
JESD218 also creates an SSD endurance rating that represents the number of TBs written by a host to the SSD (TBW), which provides a standard comparison for SSDs based on application class. A standard endurance rating will be a welcome change for end users seeking to compare SSDs from different manufacturers. In addition, the standard establishes two approaches – direct verification and extrapolation - for endurance and retention verification.
Since workloads are expected to change as applications evolve, they are described in a separate, complementary standard: JESD219. Because the workload that a SSD is subjected to has a significant impact on the amount of data that may be written to the drive, a standard workload is required to have comparable results. At the present time JESD219 defines workloads for enterprise applications only; client workloads will be added in the near future.
“Solid state drives will change the system architecture for compute applications due to their disruptive value proposition in enterprise and client compute applications. JEDEC has taken a leadership role to bring the industry together to enable broad market adoption of SSDs through industry standards with the announced standards representing a significant milestone," said Steffen Hellmold, vice president of business development at SandForce.