prova backuppc
metti in condivisione quello che vuoi backuppare dai client
backuppc poi scarica i dati, li comprime* e li archivia

*One example of disk use: 95 latops with each full backup averaging 3.6GB each, and each incremental averaging about 0.3GB. Storing three weekly full backups and six incremental backups per laptop is around 1200GB of raw data, but because of pooling and compression only 150GB is needed.

http://backuppc.sourceforge.net/info.html