There should be a mechanism that rearranges logical data blocks on the physical block device according to access patterns:
Rearrange blocks on the physical block device to optimize disk accesses.
If there is enough free space on the physical device, one could even duplicate blocks to support multiple access patterns.
To be more explicit: this is not a defragmentation mechanism. It goes even further than that: in some situations it even fragments files in order to improve performance.
