Virtualisation refers to procedures, that decouple operating systems from hardware. Normally, an operating system attunes itself to the computer hardware during installation on a system, which makes a change of hardware almost impossible without having to reinstall the OS. This usually leads to the reinstallation and reconfiguration of all application programs, which is a considerable effort.
With a Virtualisation Software typical computer functions are emulated, so that an OS does not directly access the hardware. Instead, it accesses the Virtualisation Software, which - in the eyes of the OS - acts just like a standard hardware. The Virtualisation Software then forwards commands to the real hardware. Usually, this involves a minor performance drop, which can generally be accepted.
This technique has the advantage, that if a hardware component is faulty the complete server installation can easily be run on a replacement hardware, when the identical hardware is not available. Thus, a breakdown of server hardware only entails minor delays, since the VMs can promptly be run on different hardware. Also, many so-called virtual machines (VMs) can run simultaneously on the ressources of powerful hardware. A popular software for virtualisation is VMWare, which is an Open Source product, just like bitfarm-Archiv. A server with bitfarm-Archiv Document Management can be run with a VM without problems.