Redhat Backup I Need Advice About Backup Servers?

I need advice about backup servers? - redhat backup

I need a backup server that has 20 computers connected to it.
This is what we have done:

- Automatic backup of certain documents with the client-server --
- No need to backup all files every time, only the changed files (updated backup)

I have the "server" and all 20 teams. What software do I need on the server? Customers implementing XPS and RedHat Linux.

Any help would be appreciated.