News for hackers. Stuff that matters.

A comment on Transforming a QLC SSD into an SLC SSD. Parent comment

Re:Transforming a QLC SSD into an SLC SSD by Dwedit on Sunday May 19, 2024 @12:38PM (#40408066)
You read zeroes.
[ Parent | on HN ]
Re:Transforming a QLC SSD into an SLC SSD by BeeOnRope on Sunday May 19, 2024 @05:04PM (#40409731)
Not guaranteed by default for NVMe drives. There's an NVMe feature bit for "Read Zero After TRIM" which if set for a drive guarantees this behavior but many drives of interest (2024) do not set this.
[ Parent | on HN ]
Re:Transforming a QLC SSD into an SLC SSD by Dwedit on Sunday May 19, 2024 @06:26PM (#40410214)
Hmmm, when I quick-formatted a drive (which TRIMs the whole thing), then tried reading it back in a disk hex editor, I just saw zeroes.
[ Parent | on HN ]
Re:Transforming a QLC SSD into an SLC SSD by BeeOnRope on Sunday May 19, 2024 @07:41PM (#40410595)
It seems like that would be a likely common behavior for the FTL, but it wasn't guaranteed by the spec, which is why they added this NVMe flag so that you can actually rely on it.
[ Parent | on HN ]