Destroying temporary storage in a power outage does not always work as expected

How NVMe-SSD Do they behave in the event of a power outage? This is what Russ Bishop, a developer working at Apple, wanted to know. Although data written to flash memory is safe from power outages, the same cannot be said for data that is still transit in the SSD’s cache (or cache) memory. In fact, cache memory is stored in the device’s DRAM or in a portion of the system’s random access memory (NVMe HMB protocol). That is why a flush process (Redness In English) cache memory is provided as soon as a power failure is detected. But is it effective?

Russ Bishop tested four consumer NVMe SSDs and found two to be problematic:

They are SK Hynix Gold P31 2TB SSD and Sabrent Rocket 512GB SSD. In both models, the temporary storage data was lost after disconnecting the power cable, while the cache flush process was completed successfully. On the other hand, the data is stored on Samsung 970 Evo Plus 2TB and Western Digital Red SN700 1TB SSDs.

Later, Rus Bishop conducted experiments on the following models:

• Important P5 Plus 1TB: Data retained.
• Kingston SNVS 250GB: Data retained.
• Seagate Fireguda 530 1TB: Data retained.
• Intel 670p 1TB: Data retained.
• Important P2 250GB: Data retained.
• Samsung 980 250 GB: Data retained.
• WD Black SN750 1TB: Data retained.
• WD Green SN350 240 GB: Data retained.

Most of the tested SSDs have no problem, it guarantees. As for the two faulty models, it is difficult to know whether it is a hardware or software problem. In the second case, a firmware update can provide a solution. The ball is now in the builders’ court and they have not yet reacted.

Keep in mind that enterprise SSDs have better protection against power cuts because they have capacitors that act as backup batteries. These components provide enough power to complete current operations, including cache flushing, before shutting down the SSD.

Source: Computer Base