I'm making backups of my SD card as a preventative measure using the desktop tool "SD Card Copier". Whenever I make a backup using this tool, I end up with 2GB less free space ("Available") reported by the OS on the copy. It literally vanishes from what I can tell.
For example I had ~6GB free before I copied and the duplicate it creates has ~4GB free. I see this on the SSH screen after logging in (and also in the file manager on the desktop) :
Filesystem Size Used Avail Use% Mounted on |*| /dev/root 117G 108G 3.6G 97% /
I've tried expanding the filesystem under
raspi-config which didn't change anything.
What happened to the 2GB space and how can I recover it to get the formerly available free space back to where it was before the copy (IE - Get that 2GB back)? Are there temp files created in the backup procedure that can be removed?
I'm hoping some Unix or Raspbian guru knows what's occurring here. Thanks in advance.