[balu_]

There doesn’t have to run anything special on the IPhone. In the early days iTunes could make backups on the local pc when the iPhone was connected via usb. Later on apple extended this to wifi: so if you had an iTunes running in your wifi and the iPhone joined a backup was done at the iTunes side.

I‘m not sure if this feature is still there, but I would have found this very useful if it would have been possible with the computer that is running anyways (as in the pi).