Beware: Your SSD can lose data on power outage even after proper flushing [Update]

Russ Bishop, a programmer at Apple, noticed some interesting and rather worrying behavior from some NVMe SSDs when he tested the impact of a power outage on the cached data. Bishop noticed that the drives, on registering a power cut, were losing data even after the cache was fully flushed.

For those unaware, flushing is basically the clearance of the volatile cache such that the cached data gets transferred to the non-volatile flash memory portion. Hence, doing this should in theory protect against data loss. SSD manufacturers often say their drives feature Power Loss Protection (or PLP) via hardware or firmware. However, Bishop's test suggests that at least some of these NVMe SSDs definitely lack the feature, or at least it isn't working as intended.

Fun story: I tested a random selection of four NVMe SSDs from four vendors. Half lose FLUSH’d data on power loss. That is the flush went to the drive, confirmed, success reported all the way back to userspace. Then I manually yanked the cable. Boom, data gone.
— Russ Bishop (@xenadu02) February 21, 2022

Out of the four SSDs that Bishop tested, two of them worked perfectly as they should, preventing data loss. These two models are:

Samsung 970 EVO Plus

WD Red SN700

The two other models that lost data are:

SK hynix Gold P31 2TB

Sabrent Rocket 512

Bishop says that more NVMe SSDs are on their way for testing so we will update the findings of those later.

Via: ComputerBase

Update: Test results for more NVMe SSDs have been added. Now there are four more models and thankfully, each of them passed the test. The tested drives are:

Crucial P5 Plus 1TB
Kingston NV1 250GB
Seagate FireCuda 530 1TB
Intel 670p 1TB

It was observed that the Crucial P5 Plus was consistently the "top performer". Meanwhile, for some reason, the Intel 670p SSD apparently had "odd performance quirks" when it was reconnected after the power cut.

We will update the article when more SSD results are added. So it may come in handy if you bookmark this article for re-visiting later.