What software is there for backup service?

Question

Data synchronization

You need scripts, or a ready-made solution for a remote disk space service (online backup). Protocols of interest: FTP, SFTP, rsync, SCP, Samba/CIFS, WebDAV, HTTPS.
The ability to manage:
- create\edit\delete users
- manage disk quotas for users
- manage and limit (%) the amount (in\out) of traffic allowed for a user
- view the amount of used space for a user
- notification about the use of % traffic and spaces
It will be fine if this is a solution without an API, but with the ability to change configs using, say, php.