When asking using smartctl, I got the answer:
Sector Sizes: 512 bytes logical, 4096 bytes physical
When asking using fdisk, I got the answer:
Sector size (logical/physical): 512 bytes / 512 bytes
When asking using blockdev, I got the answer:
> RO RA SSZ BSZ StartSec Size Device rw 256
> 512 4096 0 1000204886016 /dev/sdc
Why are there differences? What are the consequences of this? What do I have to do?