In order to run backups, the following components act in concert:

• the backup controller starting backups, keeping inventory records, sending out notifications
• the backup client: the system being backed up
• the backup repository: the storage holding the actual backups

In the most simple use case those roles are all implemented on the same machine. Also, a central controller is supported but not required - it is up to you if you prefer to run a controller on each client or one single central one.

You will need to install the backup software at least on the backup controller and the backup repository. The backup client can be backed up without installing the backup software (but requires SSH and rsync).

The actual backups are stored file-by-file in the same structure as on the backup client. The backup repository needs to have access to a sufficiently large storage volume (rule of thumb: at least twice the size of the data to be backed up) with a decent file system.