Despite SLC-based drives accounting for only a fraction of the NAND market, we have much more data on SLC-based SSDs than we do on those using MLC technology. Even though our data set is one-twentieth the size of previous studies on hard drives, our information starts to suggest that SLC-based SSDs are no more reliable than SAS and SATA hard drives.
If you are a consumer, this has major implications. SSD makers have been trying to emphasize that they're offering two major benefits: better performance and better reliability. However, if the data on a SSD is no safer than it is on a hard drive, then performance is the real reason you’d want to explore solid-state storage.
We're not saying that the performance of SSD isn't important (or impressive). However, as a technology, SSDs generally fall within a narrow performance spectrum. If you were to plot the speed of hard drives against solid-state drives, you would find that a low-end SSD performs about 85% faster than a hard drive. A high-end SSD only commands an 88% speed advantage.
That slim margin for differentiation is why companies like Intel preaching the message of reliability instead. As recent as the press briefing ahead of its SSD 320 launch, the company tried to hammer its point home, leaning heavily on the Hardware.fr numbers as backup. Ironically, Intel's own comparatively good reputation is why we have so much information on its SSDs. But the numbers in the field don't seem to match.
SSD performance is only going to improve, while more advanced manufacturing technology continues to push prices down. However, that means need to continue differentiating in other ways. We have to imagine that, so long as new SSDs (even the most highly-regarded ones) keep turning up with show-stopping bugs, the people who demand the utmost in data availability will continue regarding them as a maturing segment. That's why we think reliability is going to have to be the focus moving forward.
Intel gave its customers a massive dose of confidence when it upgraded the SSD 320's warranty from three years to five a couple of months back. Competing drives based on SandForce's first- and second-gen mainstream controllers and Marvell's own 6 Gb/s SSD controller are covered by three-year guarantees. Enterprise-class hard drives are generally covered by five-year warranties, too. Clearly, the impetus is on SSD vendors to sell the most reliable products possible to minimize support costs over those three or five years. But it's of course difficult to overlook the teething pains new SSDs seem to suffer as vendors fiddle with the knobs and dials that simultaneously affect performance.
- SSD Reliability: Is Your Data Really Safe?
- What Do We Know About Storage?
- A Peek Into SSD Reliability
- Data Center Feedback: Fewer Than 100 SSDs
- Steadfast Networks: More Than 100 SSDs
- Softlayer: Roughly 5000 SSDs!
- Is Reliability Important?
- Decrypting Failure Statistics: ZT Systems (~155 000 SSDs)
- Final Words