Backup Raspbian image without shutting down the Pi

It is a good idea to take a backup of the entire Raspbian image using the dd command. By this way you can restore the entire System using Win32DiskImager.exe. It is also possible to run this command without shutting down the pi (if you are running a webserver and cannot shutdown the pi. You would need the same amount of diskspace as the size of your SD card. So you will either have to mount an external usb drive or mount a network path.

Use Win32DiskImager.exe to flash this image file to the SD card to restore the OS.