I recently backed up a disk using
dd and when I tried to
dd the image back to the disk, I realized that somehow the image file is bigger in size than the original disk that was created of
original disk 7.4 GB
disk image 7.8 GB
The command I used, was:
dd if=/dev/sdg of=/mnt/data/backup.img; sync
I could not mount it, nor extract it to a directory.
What was more interesting that even PhotoRec could not recover all the data from the disk image. After getting a 16 GB flash drive and
dd'ing the disk image to it, everything could be 'recovered'.
The original flash drive contained an 8 GB partition formatted as vfat and it wasn't full. Since I did not format it before use, the factory default block size was used.
Why was the disk image ~400MB bigger than the original disk?