I run this command:
sg_unmap -v -l 0 -n 1 DEVICE
and it doesn't fail but it also doesn't do anything.
when I increase it to n=8 then it's trimming 8 lbas
why it's working like that? I couldn't figure it out from the help file.
Is there a relation between minimum number of lbas to the device's properties?
There is no minimum as such. The drive will note down that the sector can be trimmed but it can only erase an entire block when all the sectors in it are marked as discarded.
Since the presented LBA is completely unrelated to the underlying physical LBA due to the flash controller's cell management, it could potentially mean you need to mark many sectors as trimmable before it will will find a entire erase block to purge.
