Backblaze, a San Mateo, California-based backup and cloud storage company, shared data on Thursday, giving us a unique look at the reliability of SSDs over up to four years of use. Looking at the 2,906 SSDs it owned, the company tracked the failure rates of mostly consumer-grade SSDs it began using as boot drives in early Q4. quarter 2018.
Backblaze has long shared data on the reliability of hard disk drives (HDDs), but this latest report provides a new perspective on HDDs’ faster, more expensive cousins. As described in Backblaze’s blog post, the company uses SSDs for booting storage servers as well as reading, writing, and deleting log files and temporary files created by said storage servers. Backblaze said all SSDs analyzed have “similar” workloads.
Before we get into Backblaze’s first table, which shows annualized failure rates (AFRs) for 13 different SSD models, it’s important to note the limited sample size of 2,906 drives and different numbers of drives for each model. Some drives have been used more actively than others, with active days ranging from 104 days up to 724,240. So while these aren’t apples-to-apples comparisons of SSD models, the table provides a broad view of SSD reliability that the average person can’t replicate on their own.
Backblaze’s blog has several tables showing SSD failure rates, but this one looks at AFRs across the entire time Backblaze has been using SSDs. The company started using SSDs in 2018, but added most of the drives in the table below within the past three years.
The highest AFR (7.31 percent) comes from a 2TB Seagate drive, but that drive has also only been in action for 4,996 days. When looking at drives with at least 100,000 active days, the highest AFR comes from the single Crucial drive. But again, all of these drives have different drive counts and days of use.
Backblaze’s blog also highlighted the large confidence intervals in the table caused by the limited drive days of these SSDs.
“As we accumulate more data, these confidence intervals should become more accurate,” the blog said.
Backblaze said it prefers to analyze models with a confidence interval of 1 percent or less, which leaves us with two consumer-grade Seagate drives, the ZA250CM10003 with a 0.66 percent AFR and the ZA250CM10002 with a 0.96 percent AFR. Data for the Dell drive (no errors) also meets Backblaze’s confidence interval standards, but the company says this is one of the few enterprise drives in its data set and therefore difficult for consumers to obtain. Dell’s Boot Optimized Storage Solution VD is an M.2 -drive mounted on a PCIe card for server installations.
As you can see above, the drive with the highest AFR in 2022 was Seagate’s 250GB ZA250CM10002 at 1.98 percent. The SSD model had one of the largest number of drive days, and at 554 drives in count, it’s the second most abundant SSD in Backblaze’s inventory.
Seven SSDs in the table above experienced zero failures in 2022. However, Backblaze noted that six of these had only 10,000 drive days, so “there is not enough data to make a reliable projection of the failure rate for these drive models.”
Besides the Dell, which consumers would struggle to find, data for the Seagate BarraCuda 120 SSD ZA250CM10003 and BarraCuda SSD ZA250CM10002 and Crucial’s CT250MX500SSD1 are the most useful as they have at least 100,000 active days. Among these drives, the Seagate ZA250CM10003 showed the lowest AFR, 0.73 percent.
Taking it a step further back, Backblaze also shared 2020, 2021, and 2022 data for its SSDs, including four models that Backblaze added last year.
You may notice a high AFR from the Crucial 250GB CT250MX500SSD1, but note that Backblaze only added the drive in 2021, and it “recovered nicely in 2022 after having a few early failures in 2021,” according to Backblaze, which expects the trend Will continue. Crucial SSDs’ early failures coincide with the bathtub curve, which expects device failures to occur early in the release cycle before falling to a steady rate and then increasing as the product ages.
Backblaze also highlighted different AFRs from the 250GB Seagate ZA250CM10003 and 250GB Seagate ZA250CM10002.
“The Seagate drive (Model: ZA250CM10003) has delivered an AFR of less than 1% over all three years. While the AFR of the Seagate drive (Model: ZA250CM10002) fell in 2022 to almost 2%. Model ZA250CM10003 is the newer model of twice about a year. There is little difference otherwise except that the ZA250CM10003 uses less idle power, 116mW versus 185mW for the ZA250CM10002. It will be interesting to see how the younger model performs over the next year,” the blog said.
Backblaze has previously shown the reliability of SSDs over HDDs over a five-year period, but this latest data gives us a model-by-model breakdown of AFRs of SSDs in its arsenal over a slightly longer period . The longer Backblaze has these SSDs and puts them through their paces, the more insight it will be able to provide about SSD reliability.
Backblaze’s complete data set is available on its Hard Drive Test Data page.