I am running a Raspberry Pi 4 Model B as a VPN Gateway with OpenVPN. On my Samsung S8, I have the app OpenVPN for Android installed and the VPN tunnel to my home network works like a charm.
What I want to achieve now is the following: As my Raspberry Pi has an SD card with huge storage, I want to copy / backup all my images I have on my Android phone to this SD card with the folders being named just like they are on my Android phone.
I saw that rsync can be used maybe. However, I wasn't able to find a proper tutorial for my usecase: I don't want the files on the SD card in the Raspberry to be deleted - never, even when they are deleted on the phone - but only the newer images to be uploaded.
Any idea how I can achieve this?