Is it possible to determine which sectors are physically sequential given remapping for wear-leveling?
Otherwise the claimed defragmentation here is not actually resulting in sequential data.
Otherwise the claimed defragmentation here is not actually resulting in sequential data.
Which is rather a case for home use, not practical for highly parallel access industrial use cases. That's why the issue became a research topic. For the first time I saw a proof that the "fact" SSDs do not need defragmentation is actually a myth. Well, you still want to avoid explicit defragmentation (waste of time and SSD lifetime) by filesystem driver submitting additional hints (using new NVMe extensions) to the SSD controller about what blocks belong to the same file, so that SSD can place them for an optimal sequential access with properly interleaving (not necessary strictly physically consecutively whatever this means on SSD).
I haven't measured it but the SSD firmware should be able to look up where the next block is speculatively in order to be able to immediately start sending it if the host tries and read the next block (as opposed to a random one).