I have a 64GB SD card in my Raspberry Pi.
I read some guides online and the ones that looked easy to follow use a program call Win32 Disk Imager to make an image of the entire SD card.
I shutdown the Pi and when I insert the SD card in to my Windows 10 PC, I can see drive letter D:\ appear and its label is "boot"
Looking at this disk in Windows Disk management it looks a bit strange however as it has a massive unallocated area.
Anyway I proceeded to backup the disk D:\ using Win32 Disk Imager program.
It took a long time but it has created an .img file which is 27.4GB in file size.
I then put the SD card back in to the Pi and powered it on.
Here is a "df" output from the Pi
Looks like I am not using the full 64GB of the SD card.
When I first setup the Pi I was using a much smaller SD card and then I bought a decent Sandisk 64GB card and followed some other user guide found online to clone my original smaller card to the new card and expand etc.
So have I actually just backed up the Pi's SD card and all its contents successfully ?