syncosync - secure peer to peer backup synchronization
syncosync is a software for running a backup appliance, normally a
Raspberry Pi4 with a USB3 connected hard disk drive. The main function
is to receive backups from other computers on the local network and
synchronize these backups to a similar system at a different location.
The device on the other side of the network does the same, so
two devices on two sides of the network are always in sync.
You don't lose anything if something happens at either end