Which allows a virtual machine to run on two or more physical processor at the same time

There are two main hypervisor types, referred to as “Type 1” (or “bare metal”) and “Type 2” (or “hosted”). A type 1 hypervisor acts like a lightweight operating system and runs directly on the host’s hardware, while a type 2 hypervisor runs as a software layer on an operating system, like other computer programs. 

The most commonly deployed type of hypervisor is the type 1 or bare-metal hypervisor, where virtualization software is installed directly on the hardware where the operating system is normally installed. Because bare-metal hypervisors are isolated from the attack-prone operating system, they are extremely secure. In addition, they generally perform better and more efficiently than hosted hypervisors. For these reasons, most enterprise companies choose bare-metal hypervisors for data center computing needs. 

While bare-metal hypervisors run directly on the computing hardware, hosted hypervisors run on top of the operating system (OS) of the host machine. Although hosted hypervisors run within the OS, additional (and different) operating systems can be installed on top of the hypervisor. The downside of hosted hypervisors is that latency is higher than bare-metal hypervisors. This is because communication between the hardware and the hypervisor must pass through the extra layer of the OS. Hosted hypervisors are sometimes known as client hypervisors because they are most often used with end users and software testing, where higher latency is less of a concern. 

Hardware acceleration technology can create and manage virtual resources faster by boosting processing speed for both bare-metal and hosted hypervisors. A type of hardware accelerator known as a virtual Dedicated Graphics Accelerator (vDGA) takes care of sending and refreshing high-end 3-D graphics. This frees up the main system for other tasks and greatly increases the display speed of images. For industries such as oil and gas exploration, where there is a need to quickly visualize complex data, this technology can be very useful.

Both types of hypervisors can run multiple virtual servers for multiple tenants on one physical machine. Public cloud service providers lease server space on the different virtual servers to different companies. One server might host several virtual servers that are all running workloads for different companies. This type of resource sharing can result in a “noisy neighbor” effect, when one of the tenants runs a large workload that interferes with the server performance for other tenants. It also poses more of a security risk than using a dedicated bare-metal server. 

A bare-metal server that a single company has full control over will always provide higher performance than a virtual server that is sharing a physical server’s bandwidth, memory and processing power with other virtual servers. The hardware for bare-metal servers can also be optimized to increase performance, which is not the case with shared public servers. Businesses that need to comply with regulations that require physical separation of resources will need to use their own bare-metal servers that do not share resources with other tenants.

• Article
• 07/29/2021
• 5 minutes to read

Applies to: Windows Server 2022, Windows Server 2016, Microsoft Hyper-V Server 2016, Windows Server 2019, Microsoft Hyper-V Server 2019

Hyper-V is Microsoft's hardware virtualization product. It lets you create and run a software version of a computer, called a virtual machine. Each virtual machine acts like a complete computer, running an operating system and programs. When you need computing resources, virtual machines give you more flexibility, help save time and money, and are a more efficient way to use hardware than just running one operating system on physical hardware.

Hyper-V runs each virtual machine in its own isolated space, which means you can run more than one virtual machine on the same hardware at the same time. You might want to do this to avoid problems such as a crash affecting the other workloads, or to give different people, groups or services access to different systems.

Some ways Hyper-V can help you

Hyper-V can help you:

• Establish or expand a private cloud environment. Provide more flexible, on-demand IT services by moving to or expanding your use of shared resources and adjust utilization as demand changes.

• Use your hardware more effectively. Consolidate servers and workloads onto fewer, more powerful physical computers to use less power and physical space.

• Improve business continuity. Minimize the impact of both scheduled and unscheduled downtime of your workloads.

• Establish or expand a virtual desktop infrastructure (VDI). Use a centralized desktop strategy with VDI can help you increase business agility and data security, as well as simplify regulatory compliance and manage desktop operating systems and applications. Deploy Hyper-V and Remote Desktop Virtualization Host (RD Virtualization Host) on the same server to make personal virtual desktops or virtual desktop pools available to your users.

• Make development and test more efficient. Reproduce different computing environments without having to buy or maintain all the hardware you'd need if you only used physical systems.

Hyper-V and other virtualization products

Hyper-V in Windows and Windows Server replaces older hardware virtualization products, such as Microsoft Virtual PC, Microsoft Virtual Server, and Windows Virtual PC. Hyper-V offers networking, performance, storage and security features not available in these older products.

Hyper-V and most third-party virtualization applications that require the same processor features aren't compatible. That's because the processor features, known as hardware virtualization extensions, are designed to not be shared. For details, see Virtualization applications do not work together with Hyper-V, Device Guard, and Credential Guard.

What features does Hyper-V have?

Hyper-V offers many features. This is an overview, grouped by what the features provide or help you do.

Computing environment - A Hyper-V virtual machine includes the same basic parts as a physical computer, such as memory, processor, storage, and networking. All these parts have features and options that you can configure different ways to meet different needs. Storage and networking can each be considered categories of their own, because of the many ways you can configure them.

Disaster recovery and backup - For disaster recovery, Hyper-V Replica creates copies of virtual machines, intended to be stored in another physical location, so you can restore the virtual machine from the copy. For backup, Hyper-V offers two types. One uses saved states and the other uses Volume Shadow Copy Service (VSS) so you can make application-consistent backups for programs that support VSS.

Optimization - Each supported guest operating system has a customized set of services and drivers, called integration services, that make it easier to use the operating system in a Hyper-V virtual machine.

Portability - Features such as live migration, storage migration, and import/export make it easier to move or distribute a virtual machine.

Remote connectivity - Hyper-V includes Virtual Machine Connection, a remote connection tool for use with both Windows and Linux. Unlike Remote Desktop, this tool gives you console access, so you can see what's happening in the guest even when the operating system isn't booted yet.

Security - Secure boot and shielded virtual machines help protect against malware and other unauthorized access to a virtual machine and its data.

For a summary of the features introduced in this version, see What's new in Hyper-V on Windows Server. Some features or parts have a limit to how many can be configured. For details, see Plan for Hyper-V scalability in Windows Server 2016.

How to get Hyper-V

Hyper-V is available in Windows Server and Windows, as a server role available for x64 versions of Windows Server. For server instructions, see Install the Hyper-V role on Windows Server. On Windows, it's available as feature in some 64-bit versions of Windows. It's also available as a downloadable, standalone server product, Microsoft Hyper-V Server.

Supported operating systems

Many operating systems will run on virtual machines. In general, an operating system that uses an x86 architecture will run on a Hyper-V virtual machine. Not all operating systems that can be run are tested and supported by Microsoft, however. For lists of what's supported, see:

How Hyper-V works

Hyper-V is a hypervisor-based virtualization technology. Hyper-V uses the Windows hypervisor, which requires a physical processor with specific features. For hardware details, see System requirements for Hyper-V on Windows Server.

In most cases, the hypervisor manages the interactions between the hardware and the virtual machines. This hypervisor-controlled access to the hardware gives virtual machines the isolated environment in which they run. In some configurations, a virtual machine or the operating system running in the virtual machine has direct access to graphics, networking, or storage hardware.

What does Hyper-V consist of?

Hyper-V has required parts that work together so you can create and run virtual machines. Together, these parts are called the virtualization platform. They're installed as a set when you install the Hyper-V role. The required parts include Windows hypervisor, Hyper-V Virtual Machine Management Service, the virtualization WMI provider, the virtual machine bus (VMbus), virtualization service provider (VSP) and virtual infrastructure driver (VID).

Hyper-V also has tools for management and connectivity. You can install these on the same computer that Hyper-V role is installed on, and on computers without the Hyper-V role installed. These tools are:

These are some technologies from Microsoft that are often used with Hyper-V:

Various storage technologies: cluster shared volumes, SMB 3.0, storage spaces direct

Windows containers offer another approach to virtualization. See the Windows Containers library on MSDN.