>copy files to backup drive >everything but "size

because of differences in rotational velocidensity

>>61839655
fragmentation

>>61839655
Because the sector sizes for your drives are different.

>>61839655
Is it one file or many files?

>>61839749
several files, not one file

>>61839758
The tree structure change a little bit and there is one page difference. It's okay anon. Do not worry.

>>61839772
What do you mean tree structure and one page?

>>61839780
Maybe there is a system file that was not copied, and so the content of one of your directory change.

FIles are organized by page (4KB). A 1B will use 4KB space on disk. It's because CPU has instructions to map ram and hard drive (virtual memory).

So finding out which file isn't the same on disk and removing it and then cutting and pasting it and then copying it back makes it the same size on disk.

thats weird

>>61839818
Maybe you could just run your filesystem's defragmentation routine if it has such for explicit runs. The result could be the same except it might help for a while with future files too.