Business continuity plans are designed to define the processes necessary to protect organizational assets and to keep the business running in the event of a disaster or local incident. Backups and recovery are important elements to business continuity but sometimes an organization needs a shorter Recovery Time Objective (RTO). In some cases, organizations will set up hot, warm, or cold sites that allow the organization to pick up business from that location in the event of a disaster. Hot sites are immediately ready to assume the workload of the production site, while warm sites require some data to be restored to them and cold sites require servers to be turned on and possibly configured before data is loaded to them.
Virtualization assists with rapidly making systems available in an emergency because backups can be taken of entire virtual machines. This allows an organization to start up machines that have been backed up in a completely different environment without worrying about hardware compatibility. Formerly, in hot, warm, and cold sites, hardware would be identical to production sites in order to avoid possible compatibility problems during restores. This is extremely costly to an organization. With virtualization, the host machines that house the virtual servers can have different hardware from production systems without incurring compatibility problems because the hardware presented to each virtual machine is identical. The hosts do this through a process known as abstraction where virtual machines are presented with resources in a generic way but the resources are managed by a service known as a hypervisor behind the scenes.