I want to back up important data of our domain. These data consist of backing up domain server, web server, database files, and some other data files. They are located at different servers or workstations and it will be around 500 GB size. I want to back them up to an external device and keep it off site. In every 10 days, I want to connect the external device back to our network and synchronize the data in it with the updated data on the network. Synchronization needs to be done by a software, not manually.
What can be the best practice for it? What external device, software. ...?