The core functions of a virtual machine platform consist of scheduling, memory management, and maintaining a state machine (i.e., executing steps for allocating the most basic computational resources such as CPU and memory to different virtual machines). These functions are collectively called a "hypervisor." The hypervisor is responsible for creating partitions between virtual machines, and maintaining strong isolation between these partitions. The hypervisor also serves as the interface between virtual machines and external storage and data. The hypervisor is thus the most basic building block for deploying virtual infrastructure.

Since the hypervisor has complete control over the resources in all virtual machines, it has a fundamental impact on the behavior of virtualized workloads hosted on a server. Therefore, the performance and scalability of a hypervisor is a critical point of comparison in its design. The ability for a hypervisor to maintain security for virtualized resources are also important for users who plan to virtualize sensitive workloads. Finally, for the most critical workloads, hypervisors may be differentiated in their ability to reconfigure computing resources without interrupting operations of the host and/or the virtual machines.

Click on one of the links below to see how the studied server virtualization platforms compare in supporting these capabilities:

	Performance & Scalability (35 ratings)
	Dynamic Reconfiguration (6 ratings)
	Security (6 ratings)