What Makes Enterprise Grade SSDs Special Compared to Consumer Grade SSDs
When it comes to solid state storage, the phrase 'industrial-grade' is often used as a marketing tool to suggest that paying a premium means getting something more special. However, the differences between enterprise grade SSDs and consumer grade SSDs are real and often justified. In this article, we explore some of the key features and characteristics that set enterprise grade SSDs apart.
Understanding the Basics
The concept of 'industrial-grade' storage is rooted in the unique requirements of certain environments and applications. My customers began experimenting with solid state storage in 1998 while I was working at Compaq. The primary allure of SSDs in non-data center environments was their reduced susceptibility to errors and failures caused by vibration and extreme temperature conditions. Back then, we were not fully aware of the impact of the number of program erase cycles on different types of flash memory.
Flash Memory Capacity and Lifespan
It's crucial to understand that all types of flash memory storage have a finite lifespan. Single Layer Cell (SLC) flash can endure multiple times the write cycles of Multi Layer Cell (MLC) flash. This is due to the fact that SLC elements are only modified when a single bit in their cell is changed, whereas MLCs are modified multiple times because several bits are stored in each cell.
SLC vs MLC: A Comparison
Despite SLC flash being less dense, it can handle more write cycles, spread over more space, which improves heat dissipation and extends its Mean Time Between Failure (MTBF) when operating in the same environment as MLC flash storage. This makes SLC a preferred choice for systems requiring high availability, though it comes at a cost and takes up more space. On the other hand, MLC reliability has improved due to advancements in fabrication processes and smarter firmware, which can spread out where data is written.
Enterprise Grade SSD Features
Enterprise and industrial SSDs typically incorporate several key features to enhance their performance and reliability:
Error Correction Code (ECC): ECC is used to detect and correct single-bit errors in real-time. This feature is particularly useful in enterprise environments where data integrity is critical. Smarter Firmware: Modern SSD firmware is designed to reduce the likelihood of the same cells being used more frequently and to mark cells as bad if the error rate exceeds a certain threshold. Reduced Swap Operations: In the 1990s, the issue of high failure rates was often due to the operating system's swapping mechanism, leading to millions of write operations on the same cells at high rates. By increasing the amount of RAM, moving the swap file to a traditional hard drive, or modifying the code to reduce swapping, the rates of failure were significantly reduced.Conclusion
The differences between enterprise grade SSDs and consumer grade SSDs are significant, especially in environments where reliability and performance are paramount. Enterprise grade SSDs, with their advanced features and denser SLC cells, offer higher availability and better error correction, though they come at a premium. As MLC technology continues to evolve, the gap between SLC and MLC in terms of reliability is narrowing, but for critical applications, the benefits of enterprise grade SSDs remain indisputable.