Backup as a Service is a comprehensive, complete, inexpensive and easy-to-use hybrid solution for backing up and restoring selected files, folders or the entire system. It supports all common operating systems (Windows, Linux, Mac OS X , iOS, Android). It solves backup of servers, workstations, laptops, or mobile devices, plus the ability to restore files to another OS. Support for VMware vSphere, Linux KVM and Microsoft Hyper-V hypervisors.
A comparison of virtual and physical server backup options can be found HERE.