A bare-metal hypervisor (Type 1) is a layer of software we install directly on top of a physical server and its underlying hardware. There is no software or any operating system in between, hence the name bare-metal hypervisor. A Type 1 hypervisor is proven in providing excellent performance and stability since it does not run inside Windows or any other operating system. These are the most common type 1 hypervisors: + VMware vSphere with ESX/ESXi + KVM (Kernel-Based Virtual Machine) + Microsoft Hyper-V + Oracle VM + Citrix Hypervisor (formerly known as Xen Server)