You can make an image backup using Win32 Disk Imager or other similar software like it.
If you want to make a backup image of an operational system, I would advise you to use dd
. An important thing to consider here is to shut down all running processes before you make the backup using dd
so as to make sure nothing is being written/read from the SD card. Common processes to shut down would be Apache/Nginx, MySQL server and others like it.
I personally use the following command to run a backup of the SD card every night using cron and copy it to a mounted External HDD
sudo dd if=/dev/mmcblk0 bs=4096 | pv -s 7761M | sudo dd bs=4096 of=/media/NASDRIVE/backup.img
In the above code, /dev/mmcblk0
is the SD card and /media/NASDRIVE/backup.img
is the External HDD path to which dd
writes the backup image. You may omit the pv -s 7761M
part of the code but it shows a nice progress bar while backup is running.