Originally Posted by TobiSGD
OK, I shouldn't have said physical sector size, but flash block erase boundaries. Those are usually between 128K-512K and are those that have the performance impact when writing to the SSD. Partitions should be aligned to this erase boundaries
SSD controllers don't export these boundaries to the user space. There is no 1:1 mapping, because this would incur a heavy read-modify-write penalty. So you can't align partitions to erase block boundaries anyway.
If you randomly write a 4K sector anywhere on a SSD, it of course lands in a completely different erase block on the flash, than the sector before and behind it.