Server Backup Software What's The Best On-line Backup Software That I Could Install On My Server And Sell To Clients As A Service?

What's the best on-line backup software that I could install on my server and sell to clients as a service? - server backup software

I have some customers who need to find a solution for offsite backup, and I want monthly income can take ...... But I can not find that one side (backup server) that the software would be great. I know someone who has never done anything. Also open source, I would. It is necessary to manage exhange grainy and hope above all to open the files. Ideas?