How to Configure Hyper-V: A Comprehensive Guide

This blog post will teach you how to configure Hyper-V, including topics such as creating a virtual switch, creating a virtual machine, configuring virtual machine resources, and installing an operating system on a virtual machine.

1. Objective 1. Create and configure virtual machine settings
   1. Using Hyper-V Manager
   2. Creating a virtual machine
   3. Creating Generation 1 and Generation 2 VMs
2. Objective 2: Create and configure virtual machine storage
   1. Virtual disk formats
      1. Creating virtual disks
      2. Creating a virtual disk with a VM
      3. Creating a new virtual disk
      4. Adding virtual disks to virtual machines
      5. Creating differencing disks
      6. Configuring pass-through disks
      7. Modifying virtual disks
   2. Creating checkpoints
   3. Configuring Storage Quality of Service (QoS)
      1. Connecting to a storage area network (SAN)
      2. Using Fibre Channel
      3. Connecting virtual machines to a SAN
   4. Objective summary
3. Objective 3: Create and configure virtual networks
   1. Creating virtual switches
      1. Creating the default virtual switch
      2. Creating a new virtual switch
      3. Configuring MAC addresses
      4. Creating virtual network adapters
      5. Synthetic adapters and emulated adapters
      6. Configuring hardware acceleration settings
      7. Configuring advanced network adapter features
   2. Configuring NIC teaming in a virtual network environment
      1. Creating the NIC team
      2. Creating the team virtual switch
      3. Configuring a NIC team virtual network adapter
      4. Creating virtual network configurations
      5. Extending a production network into virtual space
      6. Creating an isolated network

What is hyper V

Windows Server 2012 R2 includes the Hyper-V role, which enables administrators to create virtual machines (VMs), each of which runs in its own isolated environment. VMs are self-contained units that administrators can easily move from one physical computer to another, greatly simplifying the process of deploying network applications and services.
This chapter covers some of the fundamental tasks that administrators perform to create
and deploy Hyper-V servers and VMs.

Objective 1. Create and configure virtual machine settings

Server virtualization in Windows Server 2012 R2 is based on a module called a hypervisor. Sometimes called a virtual machine monitor (VMM), the hypervisor is responsible for abstracting the computer’s physical hardware and creating multiple virtualized hardware environments, called VMs. Each VM has its own (virtual) hardware configuration and can run a separate copy of an operating system (OS). Therefore, with sufficient physical hardware and the correct licensing, a single computer running Windows Server 2012 R2 with the Hyper-V role installed can support multiple VMs, which administrators can manage as if they were standalone computers.

This objective covers how to:
■■ Configure dynamic memory
■■ Configure smart paging
■■ Configure Resource Metering
■■ Configure guest integration services
■■ Create and configure Generation 1 and Generation 2 VMs
■■ Configure and use enhanced session mode

Virtualization architectures
Virtualization products can use several different architectures to share a computer’s hardware resources among VMs. The earlier type of virtualization products, including Microsoft Windows Virtual PC and Microsoft Virtual Server, requires a standard OS installed on a computer. This becomes the “host” OS. Then you install the virtualization product, which adds the hypervisor component. The hypervisor essentially runs alongside the host OS, as shown in Figure 1-1, and enables you to create as many VMs as the computer has hardware to support.

FIGURE 1-1 A hybrid VMM sharing hardware access with a host operating system

This arrangement, in which the hypervisor runs on top of a host OS, is called Type II virtualization. By using the Type II hypervisor, you create a virtual hardware environment for each VM. You can specify how much memory to allocate to each VM, create virtual disk drives by using space on the computer’s physical drives, and provide access to peripheral devices. You then install a “guest” OS on each VM, just as if you were deploying a new computer. The host OS then shares access to the computer’s processor with the hypervisor, with each taking the clock cycles it needs and passing control of the processor back to the other.
Type II virtualization can provide adequate VM performance, particularly in classroom and laboratory environments, but it does not provide performance equivalent to separate physical computers. Therefore, it is not generally recommended for high-traffic servers in production environments.

The virtualization capability built into Windows Server 2012 R2, called Hyper-V, uses a different type of architecture. Hyper-V uses Type I virtualization, in which the hypervisor is an abstraction layer that interacts directly with the computer’s physical hardware—that is, without an intervening host OS. The term hypervisor is intended to represent the level beyond the term
supervisor, in regard to the responsibility for allocating a computer’s processor clock cycles. The hypervisor creates individual environments called partitions, each of which has its own OS installed and accesses the computer’s hardware via the hypervisor. Unlike Type II virtualization, no host OS shares processor time with the hypervisor. Instead, the hypervisor
designates the first partition it creates as the parent partition and all subsequent partitions as child partitions, as shown in
Figure 1-2

FIGURE 1-2 A Type I VMM, with the hypervisor running directly on the hardware

The parent partition accesses the system hardware through the hypervisor, just as the child partitions do. The only difference is that the parent runs the virtualization stack, which creates and manages the child partitions. The parent partition is also responsible for the subsystems that directly affect the performance of the computer’s physical hardware, such as Plug and Play, power management, and error handling. These subsystems also run in the OSs on the child partitions, but they address only virtual hardware, whereas the parent, or root, partition handles the actual hardware.

NOTE HYPER-V
It might not seem like the Hyper-V role in Windows Server 2012 R2 provides Type I virtualization,
because it requires the Windows Server OS to be installed and running. However,
adding the Hyper-V role actually converts the installed instance of Windows Server 2012
R2 into the parent partition and causes the system to load the hypervisor before the OS.

Hyper-V implementations
Windows Server 2012 R2 includes the Hyper-V role only in the Standard and Datacenter editions. The Hyper-V role is required for the OS to function as a computer’s primary partition, enabling it to host other VMs. No special software is required for an OS to function as a guest OS in a VM. Therefore, although Windows Server 2012 R2 Essentials does not include the Hyper-V role, it can function as a guest OS. Other guest OSs supported by Hyper-V include the current Windows workstation OSs and many other non-Microsoft server and workstation products.

Hyper-V licensing
The primary difference between the Standard and Datacenter editions of Windows Server 2012 R2 is the number of VMs they support. When you install a Windows Server 2012 R2 instance on a VM, you must have a license for it, just like when you install it on a physical machine. Purchasing the Datacenter edition allows you to license an unlimited number of VMs running Windows Server 2012 R2 on that one physical machine. The Standard license allows you to license only two virtual instances of Windows Server 2012R2.

IMPORTANT READERAID HEADER
Readeraid. You might find that reports vary on the specific minimum requirements of
Windows Server 2008. This is not uncommon for new operating systems because the
minimum requirements change as the operating system moves from beta to the release
candidate stage to the final RTM version. The requirements outlined in Table 1-1 are not
finalized. You might be able to get Windows Server 2008 to install on a computer that does
not meet these specifications, but the experience will be less than optimal.

Hyper-V hardware limitations
The Windows Server 2012 R2 version of Hyper-V contains massive improvements in the scalability of the system over previous versions. A Windows Server 2012 R2 Hyper-V host system can have up to 320 logical processors, supporting up to 2,048 virtual CPUs and up to 4 terabytes (TB) of physical memory. One server can host as many as 1,024 active VMs and a single VM can have up to 64 virtual CPUs and up to 1 TB of memory. Hyper-V can also support clusters with up to 64 nodes and 8,000 VMs.

NOTE WINDOWS POWERSHELL
Another major improvement in the Windows Server 2012 and Windows Server 2012 R2
versions of Hyper-V is the inclusion of a Hyper-V module for Windows PowerShell, which
includes new cmdlets dedicated to the creation and management of the Hyper-V service
and its VMs.

Hyper-V Server
In addition to the Hyper-V implementation in Windows Server 2012 R2, Microsoft provides a dedicated Hyper-V Server product, which is a subset of Windows Server 2012 R2. Hyper-V Server 2012 R2 includes the Hyper-V role, which it installs by default during the OS installation. With the exception of some limited File and Storage Services and Remote Desktop capabilities, the OS includes no other roles, as shown in Figure 1-3.

FIGURE 1-3 Roles available in Hyper-V Server

The Hyper-V Server is also limited to the Server Core interface, although as with all Server Core installation sit includes SCONFIG, a simple, script-based configuration interface, as shown in Figure 3-4. You can manage Hyper-V Server remotely by using Server Manager and Hyper-V Manager, just as you would any other Server Core installation.

FIGURE 1-4 The Server Core interface in Hyper-V Server

Unlike Windows Server 2012 R2, Hyper-V Server is a free product, available for download from Microsoft’s website. However, Hyper-V Server does not include any licenses for virtual instances. You must obtain and license all the OSs you install on the VMs you create.

Installing Hyper-V
Once you have the appropriate hardware, you can add the Hyper-V role to Windows Server 2012 R2 by using Server Manager, just as you would any other role. Adding the Hyper-V role installs the hypervisor software, and, in the case of a full GUI installation, also installs the management tools. The primary tool for creating and managing VMs and their components on Hyper-V servers is the Hyper-V Manager console. Hyper-V Manager provides administrators with a list of all the VMs on the local host and enables administrators to configure the environments of both the servers and the individual VMs. There is also a set of Hyper-V cmdlets for Windows PowerShell that enables you to exercise complete control over VMs using that interface. Microsoft recommends that you do not install other roles with Hyper-V. It is better to implement any other roles that you need the physical computer to perform within one of the VMs you create by using Hyper-V. In addition, you might want to consider installing Hyper-V on a computer by using the Server Core installation option. This will minimize the overhead expended on the partition. As with other roles, installing Hyper-V on Server Core excludes the graphical management tools, which you must install separately as a feature on another computer. Before you can install the Hyper-V role on a server running Windows Server 2012 R2, you must have the appropriate hardware:
■■ A 64-bit processor that includes hardware-assisted virtualization. This is available in processors that include a virtualization option, such as Intel Virtualization Technology (Intel VT) or AMD Virtualization (AMD-V) technology.
■■ A system BIOS that supports the virtualization hardware, on which the virtualization feature has been enabled.
■■ Hardware-enforced Data Execution Prevention (DEP), which Intel describes as eXecute Disable (XD) and AMD describes as No eXecute (NX). This is a technology used in CPUs to segregate areas of memory. Specifically, you must enable the Intel XD bit (execute disable bit) or the AMD NX bit (no execute bit). To install the Hyper-V role, use the following procedure.

1. In Server Manager, on the Manage menu, select Add Roles And Features. The Add Roles And Features Wizard starts, displaying the Before You Begin page.
2. Click Next to open the Select Installation Type page.
3. Leave the Role-Based Or Feature-Based Installation option selected and click Next. The Select Destination Server page opens.
4. Select the server on which you want to install Hyper-V and click Next. The Select Server Roles page opens.
5. Select the Hyper-V role. The Add Features That Are Required For Hyper-V dialog box appears.
6. Click Add Features to accept the dependencies and then click Next to open the Select Features page.
7. Click Next to open the Hyper-V page.
8. Click Next. The Create Virtual Switches page opens, as shown in Figure 1-5.

FIGURE 1-5 The Create Virtual Switches page of the Add Roles and Features Wizard

9. Select the appropriate check box for a network adapter and click Next. The Virtual Machine Migration page opens, as shown in Figure 1-6.

FIGURE 1-6 The Virtual Machine Migration page of the Add Roles and Features Wizard

10. Click Next to open the Default Stores page.
11. Specify alternatives to the default locations for virtual hard disk (VHD) and VM configuration files, if desired, and click Next. The Confirm Installation Selection page opens.
12. Click Install to move to the Installation Progress page as the wizard installs the role.
13. Click Close to close the wizard.
14. Restart the server. Installing the role modifies the Windows Server 2012 R2 startup procedure so that the newly installed hypervisor is able to address the system hardware directly and then load the OS as the primary partition on top of that.

NOTE USING WINDOWS POWERSHELL
You can also install the Hyper-V role by using the Install-WindowsFeature cmdlet, using the
following syntax:
Install-WindowsFeature –Name Hyper-V
-ComputerName -IncludeManagementTools -Restart

Using Hyper-V Manager

Once you have installed the Hyper-V role and restarted the computer, you can begin to create VMs and deploy OSs on them by using the Hyper-V Manager console, which you can access from the Tools menu in Server Manager.

Like most of the Windows Server 2012 R2 management tools, including Server Manager itself, you can use the Hyper-V Manager console to create and manage VMs on multiple servers, enabling administrators to exercise full control over their servers from a central location. To run Hyper-V Manager on a server that does not have the Hyper-V role, you must install the Hyper-V Management Tools feature. These tools are also found in the Remote Server

Administration Tools feature
Once you install and launch the Hyper-V Manager console, you can add servers to the display by right clicking the Hyper-V Manager node in the left pane and selecting Connect to Server from the shortcut menu. The Select Computer dialog box appears, in which you can type or browse to the name of a Hyper-V server. The Hyper-V Manager console lists all the VMs on the selected server, as shown in Figure 1-7, along with status information about each one.

FIGURE 1-7 The Hyper-V Manager console

Creating a virtual machine

After installing Hyper-V and configuring it using Hyper-V Manager, you are ready to create VMs and install the OS on each one. By using Hyper-V Manager, you can create new VMs and define the hardware resources that the system should allocate to them. In the settings for a particular VM, depending on the physical hardware available in the computer and the limitations of the guest OS, administrators can specify the number of processors and the amount of memory allotted to a VM, install virtual network adapters, and create virtual disks by using a variety of technologies, including storage area networks (SANs).

By default, Hyper-V stores the files that make up VMs in the folders you specified on the Default Stores page during the role installation. Each VM uses the following files:
■■ A virtual machine configuration file in XML format with an .xml extension that contains the VM configuration information, including all settings for the VM
■■ One or more VHD (.vhd or .vhdx) files to store the guest OS, applications, and data for the VM In addition, a VM can use a saved-state (.vsv) file if the machine has been placed into a saved state.
To create a new VM, use the following procedure.

6. Specify whether you want to create a Generation 1 or Generation 2 virtual machine
   and click Next. The Assign Memory page opens.
7. In the Startup Memory text box, type the amount of memory you want the VM to use
   and click Next. The Configure Networking page opens, as shown in Figure 1-8.

1. In Server Manager, on the Tools menu, select Hyper-V Manager to open the Hyper-V Manager console.
2. In the left pane, select a Hyper-V server.
3. From the Action menu, select New, Virtual Machine. The New Virtual Machine Wizard starts, displaying the Before You Begin page.
4. Click Next to open the Specify Name And Location page.
5. In the Name text box, type a name for the VM, keeping in mind that the system will also use this name to create the VM files and folders. To create the VM files in a location other than the default, select the Store The Virtual Machine In A Different Location check box and type an alternate path in the Location text box. Then click Next. The Specify Generation page appears.

FIGURE 1-8 The Configure Networking page of the New Virtual Machine Wizard

8. From the Connection drop-down list, select a virtual switch and click Next. The Connect Virtual Hard Disk page opens, as shown in Figure 1-9.

FIGURE 1-9 The Connect Virtual Hard Disk page of the New Virtual Machine Wizard

9. Leave the Create A Virtual Hard Disk option selected and type values for the following fields:
   ■■ Name Specifies the file name for the VHD, using the .vhdx format new to Windows Server 2012 R2
   ■■ Location Specifies a location for the VHD other than the default you specified on the Default Stores page
   ■■ Size Specifies the maximum size of the VHD
10. Click Next. The Installation Options page opens.
11. Leave the Install An Operating System Later Option selected and click Next. The Completing The New Virtual Machine Wizard page opens.
12. Click Finish. The wizard creates the new VM and adds it to the list of VMs in Hyper-V Manager. The VM that this procedure creates is the equivalent of a bare-metal computer. It has all the (virtual) hardware it needs to run, but it has no software.

NOTE USING WINDOWS POWERSHELL
To create a new VM by using Windows PowerShell, use the New-VM cmdlet with the
following basic syntax:
New-VM –Name “VM name” –MemoryStartupBytes
–NewVHDSizeBytes
For example, the following command creates a new VM called ServerA with 1 GB of
memory and a new 60-GB VHD drive:
New-VM –Name “ServerA” –MemoryStartupBytes 1GB
–NewVHDSizeBytes 60GB
There are, of course, many more parameters for the New-VM cmdlet, which you can
explore through the Get-Help cmdlet.

Each VM on a Hyper-V server consists of a collection of settings that specify the hardware resources in the machine and the configuration settings that control those resources. You can manage and modify those settings by using the Settings page for the particular VM. Selecting a VM from the list in Hyper-V Manager displays a series of icons in the Actions pane. Clicking the Settings icon opens the Settings dialog box, shown in Figure 3-10, which is the primary configuration interface for that VM. Here, you can modify any of the settings that the New Virtual Machine Wizard configured for you.

FIGURE 1-10 The Settings dialog box for a VM

Creating Generation 1 and Generation 2 VMs

In Windows Server 2012 R2, Hyper-V includes a new type of virtual machine, which it refers to as Generation 2. The VM type created by all previous versions is called Generation 1. When you create a new virtual machine in the Hyper-V manager, the New Virtual Machine Wizard includes a new page (shown in Figure 1-11) on which you specify whether you want to create a Generation 1 or Generation 2 VM. The New-VM cmdlet in Windows PowerShell also includes a new –Generation parameter.

FIGURE 1-11 The Specify Generation page in the New Virtual Machine Wizard

Generation 1 VMs are designed to emulate the hardware found in a typical computer. To do this, they use drivers for specific devices, such as an AMI BIOS, an S3 graphics adapter, and an Intel chipset and network adapter. Generation 1 VMs that you create with Windows Server 2012 R2 Hyper-V are completely compatible with all previous Hyper-V versions. Generation 2 VMs use synthetic drivers and software-based devices instead; they provide advantages that include the following:
■■ UEFI boot Instead of using the traditional BIOS, Generation 2 VMs support Secure Boot using the Universal Extensible Firmware Interface (UEFI), which requires a system to boot from digitally signed drivers and enables them to boot from drives larger than 2 TB with GUID partition tables.
■■ SCSI disks Generation 2 VMs omit the IDE disk controller used by Generation 1 VMs to boot the system and use a high-performance virtual SCSI controller for all disks, enabling the VMs to boot from VHDX files and support hot-disk adds and removes. The end result is a Generation 2 virtual machine that deploys much faster than its Generation 1 counterparts and performs better as well. The limitations, however, are that Generation 2 VMs can only run the following guest operating systems:
■■ Windows Server 2012
■■ Windows Server 2012 R2
■■ Windows 8 64-bit
■■ Windows 8.1 64-bit

Installing an operating system
Once you have created a VM, you can install an OS on it. Hyper-V in Windows Server 2012 R2 supports all the following as OSs you can install in Generation 1 VMs:
■■ Windows Server 2012 R2
■■ Windows Server 2012
■■ Windows Server 2008 R2
■■ Windows Server 2008
■■ Windows Home Server 2011
■■ Windows Small Business Server 2011
■■ Windows Server 2003 R2
■■ Windows Server 2003 SP2
■■ Windows 8.1
■■ Windows 8
■■ Windows 7 Enterprise and Ultimate
■■ Windows Vista Business, Enterprise, and Ultimate SP2
■■ Windows XP Professional SP3
■■ Windows XP x64 Professional SP2
■■ CentOS 6.0–6.2
■■ Red Hat Enterprise Linux 6.0–6.2
■■ SUSE Linux Enterprise Server 11 SP2

NOTE GUEST OSS
This is the official list of supported guest OSs at RTM. Other OSs might also function but
have not been fully tested.

One of the advantages of installing software on VMs is that there are several ways to access the installation files. A VM, by default, has a DVD drive, which can itself be physical or virtual. When you open the Settings dialog box for a Generation 1 VM and select the DVD drive in the Hardware list, you see the interface shown in Figure 1-12. In the Media section, you can select one of the following options for the drive:
■■ None The equivalent of a drive with no disk inserted
■■ Image File Points to a disk image file with a .iso extension stored on one of the host computer’s drives or on a shared network drive
■■ Physical CD/DVD Drive Links the virtual DVD drive to one of the physical DVD drives in the host computer

In a Generation 2 VM, the DVD drive supports only the None option and the Image File option, as shown in Figure 1-12. The ability to mount an image file to a virtual DVD drive is particularly useful for administrators who download OS files as disk images. Once you have mounted an installation disk, either physically or virtually, you can click Start in the Actions pane of Hyper-V Manager, which is the equivalent of turning on the VM. Starting a VM causes the thumbnail in the Hyper-V Manager to go live, displaying the contents of the computer’s screen. To display the VM’s activity at full size, click Connect in the Actions pane to open a new window for the VM. You can then interact with the VM through that window, just as if you were sitting at a physical computer’s console.

FIGURE 1-12 DVD drive settings for a VM

When the VM boots from the disk you mounted, the OS installation proceeds just as if you were using a physical computer. During the installation process, you can work with the VHD drive just as you would a physical one, creating partitions of various sizes and selecting one for the OS. When the installation is complete, the VM restarts, and you can then log on and use it in the normal manner.

Configuring Guest Integration Services
In some cases, certain Hyper-V guest OS features do not function properly using the OS’s own device drivers. Hyper-V, therefore, includes a software package called Guest Integration Services, which you can install on your VMs for compatibility purposes. Some of the functions provided by the Guest Integration Services package are as follows:
■■ Operating System Shutdown Enables the Hyper-V Manager console to remotely shut down a guest OS in a controlled manner, eliminating the need for an administrator to log on and manually shut the system down.
■■ Time Synchronization Enables Hyper-V to synchronize the OS clocks in parent and child partitions.
■■ Data Exchange Enables the Windows OSs on the parent and child partitions to exchange information, such as OS version information and fully qualified domain names.
■■ Heartbeat Implements a service in which the parent partition sends regular heartbeat signals to the child partitions, which are expected to respond in kind. A failure of a child partition to respond indicates that the guest OS has frozen or malfunctioned.
■■ Backup Enables backup of Windows VMs by using Volume Shadow Copy Services.
■■ Guest Services Enables administrators to copy files to a virtual machine without using a network connection. The Windows Server 2012, Windows Server R2, Windows 8, and Windows 8.1 operating systems have the latest Guest Integration Services software built in, so there is no need to install the package on VMs running those OSs as guests. Earlier versions of Windows have
earlier versions of the Guest Integration Services package that need to be upgraded, however, and some Windows versions do not include the package at all.

NOTE LINUX
For Linux guest OSs, you must download and install the latest release of Linux Integration
Services Version 1.4 for Hyper-V from the Microsoft Download Center. As of this writing,
the latest version is 1.4 and is available at http://www.microsoft.com/en-gb/download/
details.aspx?id=34603.

To upgrade Guest Integration Services on a Windows guest OS, use the following procedure:

1. In Server Manager, on the Tools menu, select Hyper-V Manager. The Hyper-V Manager console starts.
2. In the left pane, select a Hyper-V server.
3. In the Actions pane, start the VM on which you want to install Guest Integration Services and click Connect. A Virtual Machine Connection window opens.
4. In the Virtual Machine Connection window, from the Action menu, select Insert Integration Services Setup Disk. Hyper-V mounts an image of the Guest Integration Services disk to a virtual disk drive and an Autoplay window appears.

5. Click Install Hyper-V Integration Services. A message box appears, asking you to upgrade the existing installation.
6. Click OK. The system installs the package and prompts you to restart the computer.
7. Click Yes to restart the computer. Once you have installed or upgraded Guest Integration Services, you can enable or disable
   each of the individual functions by opening the Settings dialog box for the VM and selecting the Integration Services page, as shown in Figure 1-13.

FIGURE 1-13 Integration Services settings for a VM

At this point, you are ready to configure and manage the VM just as if you were working on a physical server. This can include modifying the network configuration, enabling remote desktop, loading the appropriate roles and features, and installing applications.

Using Enhanced Session mode
In previous versions of Hyper-V, when you open a Virtual Machine Connection window in the Hyper-V Manager console, you receive mouse and keyboard connectivity plus a limited cut and paste functionality. To obtain any further access, such as audio or print functionality, you could establish a Remote Desktop Services connection to the VM, but this requires the computers to be connected to the same network, which is not always possible.

Starting in Windows Server 2012 R2, Hyper-V supports an enhanced session mode that enables the Virtual Machine Connection window to redirect any of the following local resources to VMs running Windows Server 2012 R2 or Windows 8.1:
■■ Display configuration
■■ Audio
■■ Printers
■■ Clipboard
■■ Smart cards
■■ USB devices
■■ Drives
■■ Supported Plug and Play devices

The enhanced session mode works by establishing a Remote Desktop Protocol connection between the host computer and the VM, but it does not require a standard network path because it uses VMBus instead. VMBus is a high-speed conduit between the various partitions running on a Hyper-V server. Enhanced session mode is enabled by default in Windows 8.1, but in Windows Server 2012 R2, you must enable it on the Enhanced Session Mode Policy page of the Hyper-V Settings dialog box, as shown in Figure 1-14.

FIGURE 1-14 Enhanced Session Mode Policy settings

FIGURE 1-14 Enhanced Session Mode Policy settings

Allocating memory
Dynamic memory enables Hyper-V to adjust the amount of RAM allocated to VMs, depending on their ongoing requirements. Some computer components can be virtualized. You can take some disk space and create a virtual hard drive, and you can take an image file and create a virtual DVD drive. You can also create virtual network interface adapters and other components, which appear like the real thing in a VM. System memory is different, however. There is no substitute for memory, so all Hyper-V can do is take the physical memory installed in the computer and allocate it among the various VMs. When you create a VM, you specify how much memory to allocate to the VM. Obviously, the amount of memory available for use is based on the physical memory installed in the computer.
After you have created the VM, you can modify the amount of memory allocated to it by shutting down the VM, opening its Settings dialog box, and changing the Startup RAM setting on the Memory page, as shown in Figure 1-15. This enables you to experiment with various amounts of memory, and set the optimum performance level for the system.

FIGURE 1-15 Memory settings for a VM

USING DYNAMIC MEMORY
In the first versions of Hyper-V, shutting down the VM was the only way to modify its memory allocation. In the Windows Server 2012 R2 version, however, you can use a feature called Dynamic Memory to automatically reallocate memory to the VM from a shared memory pool as its demands change. If a virtualized server starts to experience larger amounts of client traffic,
for example, Hyper-V can increase the memory allocated to the system, and reduce it again when the traffic subsides.
To use Dynamic Memory, you must enable it by selecting the Enable Dynamic Memory check box on the VM’s Memory settings page and then configure the following settings:
■■ Startup RAM Specifies the amount of memory that you want to allocate to the VM when it starts. When you are using Dynamic Memory, this value can be the minimum amount of memory needed to boot the system.
■■ Minimum RAM Specifies the smallest amount of memory the VM can use at any time. OSs can require more memory to start up than to run, so this value can be smaller than the Startup RAM value.
■■ Maximum RAM Specifies the largest amount of memory that the VM can use at any time. The value can range from a low equal to the Startup RAM value to a high of 64 GB.
■■ Memory Buffer Specifies a percentage that Hyper-V uses to calculate how much memory to allocate to the VM, compared to its actual utilization, as measured by performance counters. For example, with the Memory Buffer value set to 20 percent,
a VM with applications and OS that consume 1 GB of memory will receive a dynamic allocation of 1.2 GB.
■■ Memory Weight Specifies a relative value that specifies the priority of this VM compared to the other VMs on the same computer. When the physical memory in the computer is insufficient to allocate the full-buffered amount specified for each VM, the VMs with the highest Memory Weight settings receive priority.

NOTE RAM
You can reduce the Minimum RAM, increase the Maximum RAM, or change the Memory
Buffer value or the Memory Weight value at any time, but to enable or disable Dynamic
Memory, you must shut down the VM.

In addition to configuring the VM settings, the guest VM must be running Windows Vista or later or Windows Server 2003 SP2 or later and have Windows Server 2012 R2 Guest Integration Services installed to use Dynamic Memory.

NOTE USING WINDOWS POWERSHELL
To configure the memory settings for a VM, use the Set-VMMemory cmdlet by using the
following basic syntax:
Set-VMMemory -DynamicMemoryEnabled $true
-MinimumBytes -StartupBytes
-MaximumBytes -Priority -Buffer
For example, to configure the memory settings for the VM ServerA, enabling Dynamic
Memory and configuring values for all of its settings, use the following command:
Set-VMMemory ServerA -DynamicMemoryEnabled $true
-MinimumBytes 64MB

CONFIGURING SMART PAGING
Dynamic Memory was introduced in Windows Server 2008 R2 Hyper-V, but Windows Server 2012 R2 improves on the concept by adding the Minimum RAM setting. This makes it possible for Hyper-V to reduce the memory used by a VM to a level lower than that needed to start the system, reclaiming that memory for other uses. The problem with having minimum RAM values that are lower than the startup RAM values is that it becomes possible to deplete the supply of physical memory with too many VMs
running simultaneously at their minimum RAM values. If this occurs, a VM that has to restart might be unable to do so because there is not enough free memory to increase its memory allocation from its minimum RAM value to its startup RAM value.
To address this possibility, Hyper-V includes a feature called smart paging. If a VM has to restart and there is not enough memory available to allocate its startup RAM value, the system uses hard disk space to make up the difference and begins paging memory contents to disk.
Disk access rates are far slower than memory access rates, of course, so smart paging incurs a severe performance penalty, but the paging occurs only for as long as it takes to restart the VM and return it to its minimum RAM allocation. Hyper-V only uses smart paging in specific conditions: when a VM must be restarted, there is no free memory available, and there are no other means available to free up the necessary memory.
You can select the Smart Paging File Location page in a VM’s Setting dialog box to specify a location for the paging file. Selecting the fastest possible hard drive is recommended.

Configuring resource metering
Resource metering is a Windows PowerShell–based feature in Windows Server 2012 R2 Hyper-V that enables administrators to document VM usage by using a variety of criteria. There are various reasons why organizations might want to track the use of VMs. For large corporations, it might be a matter of internal accounting and controlling ongoing expenses,

such as wide area network (WAN) bandwidth. For service providers, it might be necessary to bill customers based on the VM resources they use. Resource metering uses Windows PowerShell cmdlets to track a variety of performance metrics for individual VMs, including the following:
■■ CPU utilization
■■ Minimum, maximum, and average memory utilization
■■ Disk space utilization
■■ Incoming and outgoing network traffic
Resource metering statistics remain consistent, even when you transfer VMs between host systems by using Live Migration or move VHD files between VMs. To use resource metering, you must first enable it for the specific VM that you want to
monitor by using the Enable-VMResourceMetering cmdlet with the following syntax:

Enable-VMResourceMetering –VMName
Once you have enabled metering, you can display a statistical report at any time by using the Measure-VM cmdlet with the following syntax:
Measure-VM –VMName
In addition to metering resources for entire VMs, administrators can also create resource pools that enable them to monitor specific VM components, such as processors, memory, network adapters, and VHDs. You create a resource pool by using the New-VMResourcePool cmdlet and then enable metering for the pool by using Enable-VMResourceMetering. By using techniques such as pipelining, administrators can use the resource metering cmdlets to gather data on VM performance and export it to applications or data files.

Objective summary
■■ Virtualization is a process that adds a layer of abstraction between actual, physical hardware and the system making use of it. Instead of having the server access the computer’s hardware directly, an intervening component called a hypervisor creates a
VM environment, and the server OS runs in that environment.
■■ Virtualization is the process of deploying and maintaining multiple instances of an OS, called VMs, on a single computer.
■■ Microsoft Hyper-V is a hypervisor-based virtualization system for x64 computers starting with Windows Server 2008. The hypervisor is installed between the hardware and the OS and is the main component that manages the virtual computers.
■■ For licensing purposes, Microsoft refers to each VM that you create on a Hyper-V server as a virtual instance. Each Windows Server 2012 R2 version includes licenses for a set number of virtual instances; you must purchase additional licenses to license
additional instances.
■■ To keep a small footprint and minimal overhead, Hyper-V Server contains only the Windows Hypervisor, Windows Server driver model, and virtualization components.
■■ Hyper-V in Windows Server 2012 R2 supports two types of VMs: Generation 1 and Generation 2. Generation 1 VMs are designed to emulate the hardware found in a typical computer and are compatible with previous versions of Hyper-V. Generation 2
VMs use synthetic drivers and software-based devices instead and can only run on the Windows Server 2012 R2 Hyper-V.
■■ Windows Server 2012 R2 Hyper-V supports an enhanced session mode that enables the Virtual Machine Connection window to redirect a variety of local resources to VMs running Windows Server 2012 R2 or Windows 8.1.

Objective 2: Create and configure virtual machine storage

When you create a VM in Windows Server 2012 R2 Hyper-V, you emulate all the components that you typically find in a physical computer. When you virtualize memory, as discussed in Objective 3.1, “Create and configure virtual machine settings,” you take a portion of the physical memory in the computer and dedicate it to a VM. The same is true with hard disk space. Hyper-V uses a specialized VHD format to package part of the space on a physical disk and make it appear to the VM as though it is a physical hard disk drive. When you create a new Generation 1 VM in Hyper-V, the wizard creates a virtual storage subsystem that consists of two Integrated Drive Electronics (IDE) controllers and one Small Computer Systems Interface (SCSI) controller. The IDE controllers host the VM’s system drive and its DVD drive. Like their physical equivalents, each IDE controller can host two devices, so you can create two additional virtual drives and add them to the system. The SCSI controller in the default Generation 1 VM configuration is unpopulated, and you can create additional drives and add them to that controller to provide the VM with additional storage. In a Generation 2 VM, the system and DVD drives are connected to the default SCSI controller and there is no IDE alternative. In a VM of either generation, you can also create additional SCSI controllers and add drives to them. By creating multiple drives and controllers, Hyper-V makes it possible to construct virtual storage subsystems that emulate almost any physical storage solution you might devise.

This objective covers how to:
■■ Create VHDs and VHDX
■■ Configure differencing drives
■■ Modify VHDs
■■ Configure pass-through disks
■■ Manage checkpoints
■■ Implement a virtual Fibre Channel adapter
■■ Configure storage Quality of Service (QoS)

Virtual disk formats

Windows Server 2012 R2 Hyper-V supports the original VHD disk image file and the new VHDX format. The original VHD format was created by a company called Connectix for its Virtual PC product. Microsoft later acquired the product and used the VHD format for all its subsequent virtualization products, including Hyper-V. There are three types of VHD files, as
follows:

■ Fixed hard disk image An image file of a specified size in which all the disk space required to create the image is allocated during its creation. Fixed disk images can be wasteful in terms of storage because they can contain large amounts of empty space,
but they are also efficient from a performance standpoint because there is no overhead due to dynamic expansion.
■■ Dynamic hard disk image An image file with a specified maximum size, which starts small and expands as needed to accommodate the data the system writes to it. This option conserves disk space but can negatively affect performance.
■■ Differencing hard disk image A child image file associated with a specific parent image. The system writes all changes made to the data on the parent image file to the child image, to manage disk space or to facilitate a rollback at a later time. VHD images are limited to maximum size of 2 TB and are compatible with all versions of Hyper-V and Microsoft Type II hypervisor products, such as Virtual Server and Virtual PC. Windows Server 2012 introduced an updated version of the format, which uses a VHDX filename extension.
VHDX image files can be as large as 64 TB, and they also support 4-KB logical sector sizes to provide compatibility with new 4-KB native drives. VHDX files can also use larger block sizes (up to 256 MB), which enable administrators to fine-tune the performance level of a virtual storage subsystem to accommodate specific applications and data file types. However, VHDX files are not backward compatible and can only be read by Windows Server 2012, Windows Server 2012 R2, Windows 8, and Windows 8.1 Hyper-V servers. If migrating your VMs from Windows Server 2012 R2 to an older version of Hyper-V is even a remote possibility, you should continue using the VHD file format.

Creating virtual disks

Windows Server 2012 R2 Hyper-V provides several ways to create virtual disk files. You can create them as part of a VM or create them at another time and add them to a VM. The graphical interface in Hyper-V Manager provides access to most of the VHD parameters, but the Windows PowerShell cmdlets included in Windows Server 2012 R2 provide the most granular control over the disk image format.

Creating a virtual disk with a VM

The New Virtual Machine Wizard includes a Connect Virtual Hard Disk page with which you can add a single disk to your new VM. The options for this disk are relatively limited and consist of the following:
■■ Create A Virtual Hard Disk Enables you to specify the name, location, and size of a new VHD. The wizard only allows you to create a dynamically expanding disk using the VHDX format, but you can also create fixed and differencing VHDX disks using
Windows PowerShell.Use An Existing Virtual Hard Disk Enables you to specify the location of an existing VHD or VHDX disk, which the VM will presumably use as its system disk.
■■ Attach A Virtual Hard Disk Later Prevents the wizard from adding any virtual disks to the VM configuration. The assumption is that you will manually add a disk later, before you start the VM. The object of this wizard page is to create the disk on which you will install the VM’s OS or to select an existing disk on which an OS is already installed. The disk the wizard creates is
always a dynamically expanding one connected to IDE Controller 0 on a Generation 1 VM or connected to the SCSI Controller on a Generation 2 VM.

NOTE VHDS
It has become a common practice for Microsoft to release evaluation copies of its products
as preinstalled VHD files as an alternative to the traditional installable disk images. After
downloading one of these files, you can create a VM on a Hyper-V server and select the
Use An Existing Virtual Hard Disk option to mount the VHD as its system drive.

Creating a new virtual disk

1. In Server Manager, on the Tools menu, select Hyper-V Manager. The Hyper-V Manager console opens.
2. In the left pane, select a Hyper-V server.
3. From the Action menu, select New, Hard Disk to start the New Virtual Hard Disk Wizard, displaying the Before You Begin page.
4. Click Next to open the Choose Disk Format page.
5. Select one of the following disk format options:
   ■■ VHD Creates an image no larger than 2 TB, using the highly compatible VHD format
   ■■ VHDX Creates an image up to 64 TB, using the new VHDX format
6. Click Next to open the Choose Disk Type page.
7. Select one of the following disk type options:
   ■■ Fixed Size Creates a disk of a specific size, allocating all of the space at once
   ■■ Dynamically Expanding Creates a disk that can grow to the maximum size you specify as you add data
   ■■ Differencing Creates a child drive that will contain changes made to a specified parent drive
8. Click Next. The Specify Name And Location page opens.
9. Specify a file name for the disk image in the Name text box and, if desired, specify a location for the file other than the server default. Click Next to open the Configure Disk page.
10. For fixed and dynamically expanding disks, select and configure one of the following options:
    ■■ Create A New Blank Virtual Hard Disk Specifies the size (or the maximum size) of the disk image file to create
    ■■ Copy The Contents Of The Specified Physical Disk Enables you to select one of the physical hard disks in the computer and copy its contents to the new disk image
    ■■ Copy The Contents Of The Specified Virtual Hard Disk Enables you to select an existing virtual disk file and copy its contents to the new disk image
11. Click Next. The Completing The New Virtual Hard Disk Wizard page opens.
12. Click Finish.
    The wizard creates the new image disk and saves it to the specified location.

NOTE USING WINDOWS POWERSHELL
You can create new VHD files by using Windows PowerShell, which gives you more control
than is available through the graphical interface. To create a new disk image, use the
New-VHD cmdlet with the following basic syntax:
New-VHD –Path c:\filename.vhd|c:\filename.vhdx
–Fixed|-Dynamic|-Differencing –SizeBytes
[-BlockSizeBytes ]
[-LogicalSectorSizeBytes 512|4096] [-ParentPath ]
When using the cmdlet to create a disk image, the extension you specify for the filename
determines the format (VHD or VHDX); also, you can specify the block size and the logical
sector size for the image, two things you cannot do in the GUI. For example, the following
command creates a 400-GB fixed VHDX image file with a logical sector size of 4 KB:
New-VHD –Path c:\diskfile.vhdx –Fixed
–SizeBytes 400GB -LogicalSectorSizeBytes 4096

Adding virtual disks to virtual machines

Creating virtual disk image files as a separate process enables administrators to exercise more control over their capabilities, but after creating the VHD or VHDX files, you must add them to a VM for them to be useful. To add a hard disk drive to a physical computer, you must connect it to a controller; the same is true with a VM in Hyper-V. When you open the Settings dialog box for a Generation 1 VM in its default configuration, you see three controllers labeled IDE Controller 0, IDE Controller 1, and SCSI Controller. These correspond to the controllers you might find in a typical physical server computer. Each IDE controller can support two devices and the default VM configuration uses one channel on IDE Controller 0 for the system hard disk and one channel on IDE controller 1 for the system’s DVD drive. If you did not create a virtual disk as part of the new Virtual Machine
Wizard—that is, if you chose the Attach A Virtual Hard Disk Later option—then you must add a hard disk image to IDE Controller 0 to use as a system drive. A Generation 1 VM cannot boot from the SCSI controller. To add an existing virtual system drive to a VM, use the following procedure.

1. In Server Manager, on the Tools menu, select Hyper-V Manager to open the Hyper-V Manager console.
2. In the left pane, select a Hyper-V server.
3. Select a VM and, in the Actions pane, select Settings. The Settings dialog box for the VM appears.
4. Select IDE Controller 0, as shown in Figure 1-16.

FIGURE 1-16 The IDE Controller interface in the Settings dialog box

5. In the IDE Controller box, select Hard Drive and click Add. The Hard Drive page opens, as shown in Figure 3-17.

FIGURE 1-17 The Hard Drive interface in the Settings dialog box

6. In the Controller drop-down and the Location drop-down, select the IDE controller and the channel you want to use for the hard disk.
7. With the Virtual Hard Disk option selected, click Browse and select the disk image file you want to add.
8. Click OK to close the Settings dialog box. Although you cannot use a SCSI drive as the system disk in a Generation 1 VM, you can add virtual data disks to the SCSI controller. In Generation 2 VMs, you must create a SCSI system disk to boot the machine. . Unlike the IDE connectors, which support only two devices each, a SCSI connector in Hyper-V can support up to 64 drives. You can also add multiple SCSI controllers to a VM, providing almost unlimited scalability for your virtual storage subsystem.

Creating differencing disks

A 1differencing disk enables you to preserve an existing virtual disk image file in its original state while mounting it in an operating system and even modifying its contents. For example, when building a laboratory setup, you can create a baseline system by installing a clean copy of an OS on a new virtual disk and configuring the environment to fit your needs. Then you
can create a new child-differencing disk using your baseline image as the parent. All subsequent changes you make to the system will then be written to the differencing disk while the parent remains untouched. You can experiment on the test system as you wish, knowing that you can revert to your baseline configuration by just creating a new differencing disk. You can create multiple differencing disks that point to the same parent image, enabling you to populate a lab network with as many VMs as you need, which saves disk space and eliminates the need to repeatedly install the OS. To create a cloned version of a baseline installation with a differencing disk, use the following procedure.

1. Install and configure the baseline VM Create a new VM with a new disk image file and install a guest OS on it. Configure the OS as needed and install any roles, features, applications, or services you need.
2. Generalize the parent image Open an elevated command prompt on the baseline system and run the Sysprep.exe utility with the appropriate parameters for your requirements. Sysprep configures the system to assign itself a new, unique security ID (SID) the next time the computer starts. This enables you to create multiple cloned systems from a single disk image.
3. Create a parent disk image Once you have generalized the baseline installation, you no longer need the original VM. You can delete everything except the VHD or VHDX file containing the disk image. This will become your parent image. Open the Properties sheet for the image file and set the read-only flag to ensure that the baseline does not change.
4. Create a differencing disk By using the New Virtual Hard Disk Wizard or the New VHD cmdlet for Windows PowerShell, create a new differencing disk pointing to the baseline image you created and prepared earlier as the parent image.
5. Create a cloned VM Create a new VM and, on the Connect Virtual Hard Disk page, attach the differencing disk you just created to it by using the Use An Existing Virtual Hard Disk option. You can then proceed to create additional cloned VMs with differencing disks that all use the same parent. Each one can function independently and the parent disk will remain
   unchanged. When you create a differencing drive by using the New Virtual Hard Disk Wizard, selecting the Differencing option on the Choose Disk Type page causes the Configure Disk page to

appear as shown in Figure 1-18. In the Location text box, specify the name of the file that you want to use as the parent image.
In the same way, if you create the differencing disk by using Windows PowerShell, you must run the New-VHD cmdlet with the –Differencing parameter and the –ParentPath parameter, specifying the location of the parent disk.

FIGURE 1-18 The Configure Disk page in the New Virtual Hard Disk Wizard

Configuring pass-through disks

This objective has thus far been concerned primarily with VHDs, areas of space on a physical disk drive allocated for use by VMs. However, it is also possible for VMs to access physical disks directly.
A pass-through disk is a type of virtual disk that points to a physical disk drive installed on the host computer. When you add a hard drive to any of the controllers in a VM, you have the option of selecting a physical hard disk as opposed to a virtual one.
To add a physical hard disk to a VM, the VM must have exclusive access to it. This means that you must first take the disk offline in the parent OS by using the Disk Management snap-in, as shown in Figure 1-19, or the Diskpart.exe utility. Once the disk is offline, it will be available for selection in the Physical Hard Disk drop-down list.

FIGURE 1-19 An offline disk in the Disk Management snap-in

Modifying virtual disks

1. In Server Manager, on the Tools menu, select Hyper-V Manager to open the Hyper-V Manager console.
2. In the left pane, select a Hyper-V server.
3. In the Actions pane, select Edit Disk. The Edit Virtual Hard Disk Wizard starts, displaying the Before You Begin page.
4. Click Next to open the Locate Disk page.
5. Type or browse to the name of the VHD or VHDX file you want to open and click Next. The Choose Action page appears.
6. Select one of the following functions:
   ■■ Compact Reduces the size of a dynamically expanding or differencing disk by deleting empty space while leaving the disk’s capacity unchanged
   ■■ Convert Changes the type of format of a disk by copying the data to a new disk image file
   ■■ Expand Increases the capacity of the disk by adding empty storage space to the image file
   ■■ Shrink Reduces the capacity of the disk by deleting empty storage space from the file
   ■■ Merge Combines the data on a differencing disk with that of the parent disk to form a single composite image file
7. Click Next to open the Completing The Edit Virtual Hard Disk Wizard page.
8. Complete any new pages presented by the wizard as a result of your selection and click Finish. The options that appear on the wizard’s Choose Action page depend on the current status of the image file you select. For example, the Merge option only appears if you choose a differencing disk, and the Shrink option does not appear unless there is free space in the file that the wizard can delete. In addition to these disk-editing functions provided by Hyper-V Manager, it is possible to use the Disk Management snap-in on the Hyper-V host to mount a VHD or VHDX file as a drive and access its contents, just as if it were a physical disk.
9. To mount a VHD file, use the following procedure.
10. In Server Manager, on the Tools menu, select Computer Management to open the Computer Management console.
11. In the left pane, select Disk Management. The Disk Management snap-in opens.
12. From the Action menu, select Attach VHD. The Attach Virtual Hard Disk dialog box appears.
13. In the Location text box, type or browse to the image disk file you want to attach and click OK. The disk appears in the Disk Management interface.
14. Close the Computer Management console. At this point, you can work with the virtual disk and its contents using any standard tools, just as you would a physical hard disk drive. To detach the VHD, you use the same procedure
    and select Detach VHD from the Action menu.

Creating checkpoints

In Hyper-V, a checkpoint is a captured image of the state, data, and hardware configuration of a VM at a particular moment in time. Creating checkpoints is a convenient way for administrators to revert a VM to a previous state at will. For example, if you create a checkpoint just before applying a system update, and the update is somehow problematic, you can apply the
checkpoint and return the VM to the state in which it was before you applied the update.

Creating a checkpoint is as simple as selecting a running VM in Hyper-V Manager and selecting Checkpoint from the Actions pane. The system creates a checkpoint file with an AVHD or AVHDX extension, in the same folder as the VHD file, and adds the checkpoint to the Hyper-V Manager display, as shown in Figure 1-20.

FIGURE 1-20 A checkpoint in Hyper-V Manager

Checkpoints are a useful tool for administrators implementing a test environment in Hyper-V, but they are not recommended for heavy use in production environments. In addition to consuming disk space, the presence of checkpoints can reduce the overall performance of a VM’s disk subsystem. Administrators also should not use checkpoints on VMs containing databases—such as those created by SQL Server, Exchange, or Windows domain controllers—because the checkpointing process does not account for the current state of the database, and corruption might occur.

Configuring Storage Quality of Service (QoS)

Because it is common for there to be more than one virtual hard disk hosted by a single physical hard disk, it is possible for one virtual disk to monopolize the input/output capacity of a physical disk, causing the other virtual disks to slow down. To help prevent this, Windows Server 2012 R2 enables you to control the Quality of Service (QoS) for a given virtual hard
disk. QoS management in Hyper-V takes the form of controls that enables you to specify the minimum and maximum input/output operations per second (IOPS) for a disk. To configure storage QoS, open the Settings dialog box for a VM, expand a hard drive component, and select Advanced Features to display the Advanced Features page shown in Figure 1-21.

FIGURE 1-21 Storage Quality of Service controls in Hyper-V Manager

After selecting the Enable Quality of Service Management check box, you can specify Minimum IOPS values and Maximum IOPS values for the disk in 8 KB increments.

Connecting to a storage area network (SAN)

At its most basic level, a storage area network (SAN) is simply a network dedicated to highspeed connections between servers and storage devices. Instead of installing disk drives into servers or connecting them by using an external SCSI bus, a SAN consists of one or more drive arrays equipped with network interface adapters, which you connect to your servers by using standard twisted pair or fiber optic network cables. A SAN-connected server, therefore, typically has at least two network adapters, one for the standard local area network (LAN) connection and one for the SAN, as shown in Figure 1-22.

FIGURE 1-22 A server connected to a SAN

The advantages of SANs are many. By connecting the storage devices to a network instead of to the servers themselves, you avoid the limitations imposed by the maximum number of devices you can connect directly to a computer. SANs also provide added flexibility in their communications capabilities. Because any device on a SAN can conceivably communicate
with any other device on the same SAN, high-speed data transfers can occur in any of the following ways:
■■ Server to storage Servers can access storage devices over the SAN just as if they were connected directly to the computer.
■■ Server to server Servers can use the SAN to communicate directly with one another at high speeds to avoid flooding the LAN with traffic.
■■ Storage to storage Storage devices can communicate among themselves without server intervention, for example, to perform backups from one medium to another or to mirror drives on different arrays. Although a SAN is not in itself a high-availability technology, you can make it one by connecting redundant servers to the same network, as shown in Figure 3-23, enabling them to
access the same data storage devices. If one server should fail, another can assume its roles by accessing the same data. This is called server clustering.

FIGURE 1-23 Multiple servers connected to a SAN

Because they use standard networking technologies, SANs can also greatly extend the distances between servers and storage devices. You can design a SAN that spans different rooms, different floors, or even different buildings, just as you would a standard computer network.
Servers and storage devices cannot exchange SCSI commands over a SAN connection the way they do when the devices are directly connected using a SCSI cable. To communicate over a SAN, servers and storage devices map their SCSI communications onto another protocol, such as Fibre Channel.

Using Fibre Channel

Fibre Channel is a versatile SAN communications technology supporting various network media, transmission speeds, topologies, and upper-level protocols. Its primary disadvantage is that it requires specialized hardware that can be extremely expensive.

MORE INFORMATION FIBRE CHANNEL
The nonstandard spelling of the word fibre in Fibre Channel is deliberate, to distinguish the
term from fiber optic. Fibre Channel can run on either twisted-pair copper cables or it can
run on optical cables, whereas the spelling fiber always refers to an optical medium.

Installing a traditional Fibre Channel SAN entails building an entirely new network with its own special medium, switches, and network interface adapters. In addition to the hardware costs, which can easily be 10 times those of a traditional Ethernet network, there are also installation and maintenance expenses to consider. Fibre Channel is a rather esoteric technology, with relatively few experts in the field. To install and maintain a Fibre Channel SAN, an organization must either hire experienced staff or train existing personnel on the new technology. However, there is also a variant called Fibre Channel over Ethernet (FCoE) that uses standard Ethernet hardware and is therefore much less expensive.

Connecting virtual machines to a SAN

The specialized networking technologies used to build Fibre Channel SANs have, in the past, made it difficult to use them with virtualized servers. However, since the Windows Server 2012 implementation, Hyper-V has supported the creation of virtual Fibre Channel adapters. A Hyper-V Fibre Channel adapter is essentially a pass-through device that enables a VM to access a physical Fibre Channel adapter installed in the computer, and through that, to access the external resources connected to the SAN. With this capability, applications running on VMs can access data files stored on SAN devices and administrators can use VMs to create
server clusters with shared storage subsystems. To support virtual Fibre Channel connectivity, the physical Fibre Channel host bus
adapter(s) in the host computer must have drivers that explicitly support virtual Fibre Channel. This support is relatively rare, but more manufacturers are expected to update their drivers to provide the necessary support. Your SAN must also be able to address its connected resources by using logical unit numbers (LUNs). Assuming you have the appropriate hardware and software installed on the host computer, you implement the Fibre Channel capabilities in Hyper-V by first creating a virtual SAN by using the Virtual SAN Manager, accessible from Hyper-V Manager. When you create the virtual SAN, the World Wide Node Names (WWNNs) and World Wide Port Names (WWPNs) of your host bus adapter appear, as shown in Figure 1-24.

FIGURE 1-24 WWNNs and WWPNs in a virtual SAN

The next step is to add a Fibre Channel adapter to a VM from the Add Hardware page in the Settings dialog box. When you do this, the virtual SAN you created earlier is available on the Fibre Channel Adapter page, shown in Figure 1-25. Hyper-V virtualizes the SAN and makes the WWNNs and WWPNs available to the VM.

FIGURE 1-25 A Fibre Channel adapter in a VM

Thought experiment
Creating a VHD
In the following thought experiment, apply what you’ve learned about this objective
to predict what steps you need to take. You can find answers to these questions
in the “Answers” section at the end of this chapter.
Ed wants to create a new VHD file on his Hyper-V server by using Windows Power-
Shell. He runs the Get-Disk cmdlet and receives the following results:
Operational Total Partition
Number Friendly Name Status Size Style
0 WDC WD5003ABYX-18WERA0 Online 465.76 GB MBR
1 WDC WD1002FAEX-00Z3A0 Online 931.51 GB GPT
What command should Ed use to create a new 500-GB fixed VHD for his Server A
VM, in the Windows Server 2012 R2 format, using data from the 465-GB drive on his
computer, and a 4,096-byte sector size?

Objective summary

Hyper-V uses a specialized VHD format to package part of the space on a physical disk and make it appear to the VM as though it is a physical hard disk drive.
■■ A dynamic hard disk image is an image file with a specified maximum size, which starts small and expands as needed to accommodate the data the system writes to it.
■■ A differencing hard disk image is a child image file associated with a specific parent image. The system writes all changes made to the operating system to the child image, to facilitate a rollback at a later time.
■■ VHDX image files in Windows Server 2012 R2 can be as large as 64 TB, and they also support 4-KB logical sector sizes to provide compatibility with new 4-KB native drives.
■■ A pass-through disk is a type of virtual disk that points to a physical disk drive installed on the host computer.
■■ In Hyper-V, a checkpoint is a captured image of the state, data, and hardware configuration of a VM at a particular moment in time.
■■ QoS management in Hyper-V takes the form of controls that enable you to specify the minimum and maximum input/output operations per second (IOPS) for a disk.
■■ The specialized networking technologies used to build Fibre Channel SANs have, in the past, made it difficult to use them with virtualized servers. However, Windows Server 2012 R2 Hyper-V supports the creation of virtual Fibre Channel adapters.

Objective 3: Create and configure virtual networks

Networking is a critical part of creating a VM infrastructure. Depending on your network plan, the VMs you create on a Windows Server 2012 R2 Hyper-V server can require communication with other VMs, with the computers on your physical network, and with the Internet. When you build a network out of physical computers, you install a network interface adapter in each one and connect it to a hardware switch. The same principle is true in a Hyper-V environment, except that you use virtual components instead of physical ones. Each VM you create has at least one virtual network adapter and you can connect that adapter to
a virtual switch. This enables you to connect the VMs on your Hyper-V server in various network configurations that either include or exclude the systems on your physical network. You can create multiple virtual switches on a Hyper-V server and multiple network adapters in each VM. This enables you to create a flexible networking environment that is suitable
for anything from a laboratory or classroom network to a production environment. In addition, Windows Server 2012 R2 has added the ability to create extensions for virtual switches so that software developers can enhance their capabilities.

This objective covers how to:
■■ Implement Hyper-V Network Virtualization
■■ Configure Hyper-V virtual switches
■■ Optimize network performance
■■ Configure MAC addresses
■■ Configure network isolation
■■ Configure synthetic and legacy virtual network adapters
■■ Configure network interface card (NIC) teaming in VMs

Creating virtual switches

A virtual switch, like its physical counterpart, is a device that functions at Layer 2 of the Open Systems Interconnect (OSI) reference model. A switch has a series of ports, each of which is connected to a computer’s network interface adapter. Any computer connected to the switch can transmit data to any other computer connected to the same switch. Unlike physical switches, the virtual switches created by Hyper-V can have an unlimited number of ports, so administrators don’t have to be concerned about connecting switches together or about uplinks and crossover circuits.

Creating the default virtual switch

The Windows Server 2012 R2 Add Roles and Features Wizard provides the opportunity to create virtual switches when you install the Hyper-V role. When you install Hyper-V on a server running Windows Server 2012 R2, the Create Virtual Switches page provides you wit the opportunity to create a virtual switch for each of the physical network adapters installed in the host computer. These switches enable VMs to participate on the networks to which the physical adapters are connected.
When you create a virtual switch, the networking configuration in the host OS on the parent partition changes. The new virtual switch appears in the Network Connections window, and if you examine its properties, you can see that the switch is bound to the operating system’s TCP/IP client, as shown in Figure 1-26.
Meanwhile, Hyper-V also changes the properties of original network connection representing the physical network interface adapter in the computer. The physical network adapter is now bound only to the virtual switch, as shown in Figure 1-27.
As a result, the computer’s physical network configuration, in which its network adapter is connected to an external physical switch, is overlaid by the virtual network configuration created by Hyper-V. In this virtual configuration, the virtual switch is connected to the physical switch and the network adapter in the host OS is connected to the virtual switch.

The internal virtual network and the external physical network are joined into a single LAN, just as if you connected two physical switches.

FIGURE 1-26 A virtual switch and its properties, displayed in the host OS

FIGURE 1-27 A network interface adapter in the host OS, bound to a virtual switch

Once Hyper-V has created the virtual switch and made these configuration changes, any new VMs that administrators choose to connect to the virtual switch become part of this conjoined network, as do any physical computers connected to the physical network through an external switch.

This type of virtual switch is, in Hyper-V terminology, an external network switch because it provides connections external to the Hyper-V environment. This is typically the preferred arrangement for a production network in which Hyper-V VMs provide and consume services for the entire network.
For example, a VM connected to this switch will automatically obtain an IP address from a Dynamic Host Configuration Protocol (DHCP) server on the physical network, if there is one.
As an alternative, you could configure a VM as a DHCP server and let it provide addresses to all of the systems on the network, virtual or physical.
Perhaps more important, this arrangement can also enable your VMs to access the Internet by using the router and DNS servers on the external network. The VMs can then download OS updates from servers on the Internet, just as external machines often do.
There are situations in which this type of virtual switch is inappropriate. If you are creating a laboratory network for product testing or a classroom network, you might not want it to be accessible to or from the external network. In these cases, you must create a different type of virtual switch by using the Virtual Switch Manager in Hyper-V Manager.

Creating a new virtual switch

Hyper-V in Windows Server 2012 R2 supports three types of switches, which you must create in the Virtual Switch Manager before you can connect VMs to them.
To create a new virtual switch, use the following procedure.

1. In Server Manager, on the Tools menu, select Hyper-V Manager to open the Hyper-V Manager console.
2. In the left pane, select a Hyper-V server.
3. From the Actions pane, select Virtual Switch Manager. The Virtual Switch Manager dialog box for the Hyper-V server opens, as shown in Figure 1-28.

FIGURE 1-28 The Virtual Switch Manager dialog box

4. In the Create Virtual Switch section, select one of the following switch types:
   ■■ External The virtual switch is bound to the networking protocol stack in the host OS and connected to a physical network interface adapter in the Hyper-V server. VMs running on the server’s parent and child partitions can all access the physical
   network to which the physical adapter is connected.
   ■■ Internal An internal network switch is bound to a separate instance of the networking protocol stack in the host OS, independent from the physical network interface adapter and its connected network. VMs running on the server’s parent
   and child partitions can all access the virtual network implemented by the virtual switch; the host OS on the parent partition can access the physical network through the physical network interface adapter, but the VMs on the child partitions cannot
   access the physical network through the physical adapter.
   ■■ Private A private network switch exists only in the Hyper-V server and is accessible only to the VMs running on the child partitions. The host OS on the parent partition can access the physical network through the physical network interface
   adapter, but it cannot access the virtual network created by the virtual switch.
5. Click Create Virtual Switch to open the Virtual Switch Properties page.
6. Configure the following options, if desired:
   ■■ Allow Management Operating System To Share This Network Adapter Selected by default when you create an external virtual switch, clearing this check box excludes the host OS from the physical network while allowing access to the child VMs.
   ■■ Enable Single Root I/O Virtualization (SR-IOV) Enables you to create an external virtual switch that is associated with a physical network adapter capable of supporting SR-IOV. This option is only available when creating a new virtual switch;
   you cannot modify an existing virtual switch to use this option.
   ■■ Enable Virtual LAN Identification For Management Operating System If your host computer is connected to a physical switching infrastructure that uses virtual LANs (VLANs) to create separate subnets, you can select this check box and enter a VLAN identifier to associate the virtual switch with a particular VLAN on your physical network.
7. Click OK. The new virtual switch appears in the left pane, in the list of virtual switches. You can create additional virtual switches as needed. You can create only one external switch for each physical network adapter in the computer, but you can create multiple internal or private switches to create as many virtual networks as you need.

NOTE USING WINDOWS POWERSHELL
To create a new virtual switch by using Windows PowerShell, use the New-VMSwitch
cmdlet with the following basic syntax:
New-VMSwitch -NetAdapterName
[-SwitchType Internal|Private]
For example, to create an external switch called LAN Switch, you would use the following
command:
New-VMSwitch “LAN Switch” –NetAdapterName “Ethernet”

Configuring MAC addresses

Every network interface adapter has a Media Access Control (MAC) address—sometimes called a hardware address—that uniquely identifies the device on the network. On physical network adapters, the MAC is assigned by the manufacturer and permanently entered in the adapter’s firmware. The MAC address is a 6-byte hexadecimal value, the first three bytes of
which are an organizationally unique identifier (OUI) that specifies the manufacturer, and the last three bytes of which identify the adapter itself.

The MAC address is essential to the operation of a LAN, so the virtual network adapters on a Hyper-V server need to have them. The server has at least one real MAC address, provided in its physical network adapter, but Hyper-V cannot use that one address for all the virtual adapters connecting VMs to the network.
Instead, Hyper-V creates a pool of MAC addresses during the installation of the role and it assigns addresses from this pool to VMs as you create them. To view or modify the MAC address pool for the Hyper-V server, you open the Virtual Switch Manager and, under Global Network Settings, select MAC Address Range, as shown in Figure 1-29.

FIGURE 1-29 The MAC Address Range in the Virtual Switch Manager

The first three bytes of the MAC address range are always 00-15-5D, which is an OUI registered by Microsoft. The fourth and fifth bytes of the MAC address are the last two bytes of the IP address assigned to the server’s physical network adapter, converted to hexadecimal notation. The sixth and last byte of the MAC address contains the range of values from 00 to
FF, which provides 256 possible addresses.

The Hyper-V server assigns the MAC addresses to the network adapters in VMs as administrators create the adapters. The adapters retain their MAC addresses permanently or until the adapter is removed from the VM. The server reclaims any unused addresses and reuses them.
The default pool of 256 addresses is expected to be sufficient for most Hyper-V VM configurations, but if it is not, you can modify the Minimum and Maximum values to enlarge the pool. To prevent address duplication, you should change the second-to-last byte only, making it into a range of addresses like the last byte.
For example, the range illustrated in the figure provides 256 addresses with the following values:
00-15-1D-02-12-00 to 00-15-1D-02-12-FF
Modifying only the least significant digit, as in the following values, increases the pool from 256 to 4,096:
00-15-1D-02-10-00 to 00-15-1D-02-1F-FF

WARNING MAC ADDRESSES
When you modify the MAC address pool and you have other Hyper-V servers on your
network, you must be careful not to create an overlap situation in which duplicate MAC
addresses can occur or networking problems can result.

Creating virtual network adapters

Once you have created virtual switches in Hyper-V Manager, you can connect VMs to them by creating and configuring virtual network adapters. When you create a new VM, the default configuration includes one virtual network adapter. The New Virtual Machine Wizard includes a Configure Networking page, on which you can select one of the virtual switches you have
created.
If you have created only the default external virtual switch when installing Hyper-V, then connecting a VM to that switch joins the system to the physical network. If you want to create additional network adapters in your VMs, you must use the following procedure.

1. In Server Manager, on the Tools menu, select Hyper-V Manager to open the Hyper-V Manager console.
2. In the left pane, select a Hyper-V server.
3. In the Virtual Machines list, select a VM and, in the Actions pane, click Settings. The Settings dialog box for the VM appears.
4. In the Add Hardware list, select Network Adapter and click Add. A new adapter appears in the Hardware list, as shown in Figure 3-307.

FIGURE 1-30 A new network adapter in the Settings dialog box

5. In the Virtual Switch drop-down list, select the switch to which you want to connect the network adapter.
6. If your host computer is connected to a physical switching infrastructure that uses VLANs to create separate subnets, you can select the Enable Virtual LAN Identification check box and enter a VLAN identifier to associate the network adapter with a particular VLAN on your physical network.
7. To control the amount of network bandwidth allocated to the network adapter, select the Enable Bandwidth Management check box and supply values for the Minimum Bandwidth and Maximum Bandwidth settings.
8. Click OK. The settings are saved to the VM configuration. You can create up to 12 network adapters on a Windows Server 2012 R2 Hyper-V server: eight synthetic and four emulated.

Synthetic adapters and emulated adapters

Selecting the Network Adapter option on the Add Hardware page creates what is known in Hyper-V terminology as a synthetic network adapter. Hyper-V supports two types of network and storage adapters: synthetic and emulated (sometimes called legacy).
A synthetic adapter is a purely virtual device that does not correspond to a real-world product. Synthetic devices in a VM running on a child partition communicate with the parent partition by using a high-speed conduit called the VMBus.
The virtual switches you create in Hyper-V reside in the parent partition and are part of a component called the network Virtualization Service Provider (VSP). The synthetic network adapter in the child partition is a Virtualization Service Client (VSC). The VSP and the VSC are both connected to the VMBus, which provides interpartition communications, as shown
in Figure 3-31. The VSP, in the parent partition, provides the VSC, in the child partition, with access to the physical hardware in the host computer; that is, the physical network interface adapter.

FIGURE 1-31 Synthetic network adapters communicate by using the VMBus

Because they have access to the hardware through the VMBus, synthetic adapters provide a much higher level of performance than the alternative, emulated adapters. Synthetic adapters are implemented as part of the Guest Integration Services package that runs on supported guest OSs. The main drawback of synthetic network adapters is that they are not
operational until the OS is loaded on the VM.
An emulated adapter—sometimes called a legacy adapter—is a standard network adapter driver that communicates with the parent partition by making calls directly to the hypervisor, which is external to the partitions, as shown in Figure 1-32. This communication method is substantially slower than the VMBus used by the synthetic network adapters and is therefore
less desirable.

FIGURE 1-32 Emulated network adapters communicate by using the hypervisor

To install an emulated adapter, you use the same procedure described earlier, except that you select Legacy Network Adapter from the Add Hardware list. Unlike synthetic adapters, emulated adapters load their drivers before the OS, so it is possible to boot the VM by using the Preboot eXecution Environment (PXE) and then deploy an OS over the network.
This is one of two scenarios in which using an emulated adapter is preferable to using a synthetic adapter. The other is when you are installing an OS on your VMs that does not have a Guest Integration Services package available for it.

Configuring hardware acceleration settings

Some physical network interface adapters have features that are designed to improve performance by offloading certain functions from the system processor to components built into the adapter itself. Hyper-V includes support for some of these features, as long as the hardware in the physical network adapter supports them properly.
When you expand a network adapter in the Settings dialog box of a VM, you gain access to the Hardware Acceleration page. On this page, you can configure the following hardware acceleration settings:
■■ Enable Virtual Machine Queue Virtual machine queue (VMQ) is a technique that stores incoming packets intended for VMs in separate queues on the physical network adapter and delivers them directly to the VMs, bypassing the processing normally
performed by the virtual switch on the parent partition.

■■ Enable IPsec Task Offloading Uses the components on the network adapter to perform some of the cryptographic functions required by IPsec. You can also specify the maximum number of security associations you want the adapter to be able to
calculate.
■■ Single-Root I/O Virtualization Enables the virtual adapter to take advantage of the SR-IOV capabilities of the physical adapter.

Configuring advanced network adapter features

The Advanced Features page provides additional options for supporting network adapter capabilities, as follows:
■■ Static MAC Address By default, virtual network adapters receive a dynamically assigned MAC address from the Hyper-V server. However, you can opt to create a static MAC address by using this option. The only requirement is that no other adapter,
virtual or physical, on the same network uses the same address.
■■ Enable MAC Address Spoofing When enabled, the port in the virtual switch to which the virtual network adapter is connected can send and receive packets that contain any MAC address. The virtual switch port can also learn of new MAC addresses
and add them to its forwarding table.
■■ Enable DHCP Guard Prevents the adapter from processing messages sent by rogue DHCP servers.
■■ Port Mirroring Mode Enables the adapter to forward all the packets it receives over the network to another virtual adapter for analysis by using an application such as Network Monitor.
■■ NIC Teaming Enables the adapter to add its bandwidth to that of other adapters in the same guest OS in a NIC teaming arrangement.

Configuring NIC teaming in a virtual network environment

As explained in objective 1.2, “Configuring Servers,” NIC teaming is a Windows feature that enables administrators to join multiple network adapters into a single entity for performance enhancement or fault tolerance purposes. Hyper-V virtual machines can also take advantage of NIC teaming, but they are limited to teams of only two, as opposed to the host operating
system, which can have teams of up to 64 NICs.
To use NIC teaming in Hyper-V, you must complete three basic tasks, as follows:

1. Create the NIC team in the Windows Server 2012 R2 host operating system.
2. In Hyper-V Manager, create an external virtual switch using the NIC team.
3. Configure the network adapter in a virtual machine to connect to the virtual switch representing the NIC team.

Creating the NIC team

NIC teams must consist of physical network interface adapters, so before you can use a NIC team in a virtual machine, you must create it in the host operating system. After installing two NICs in the computer, you can create a NIC team with Server Manager in the usual manner, using the settings shown in Figure 3-33. Creating the team installs the Microsoft Network Adapter Multiplexor Driver, which appears as one of the components of the network connection representing the team.

FIGURE 1-33 The NIC Teaming dialog box

Creating the team virtual switch

Once you have created the NIC team, you can open the Virtual Switch Manager and create a new virtual switch by selecting the External network option and choosing Microsoft Network Adapter Multiplexor Driver from the drop-down list,
as shown in Figure 1-34.

FIGURE 1-34 The Virtual Switch Properties settings for a NIC team switch

Configuring a NIC team virtual network adapter

To configure a virtual machine to use a NIC team, you must use the Settings dialog box to modify the properties for a virtual network adapter, configuring it to use the team switch you created in the previous section, as shown in Figure 1-35.

FIGURE 1-35 The Network Adapter settings for a NIC team adapter

Finally, you must open the Advanced Features page for the network adapter and select the Enable The Network Adapter To Be Part Of A Team In The Guest Operating System check box.
At this point, the NIC team is operational for the virtual machine. You can unplug one of the
network cables and the system will maintain its connection to the network.

Creating virtual network configurations

Hyper-V makes it possible to extend nearly any existing physical network configuration into its virtual space or create a completely separated and isolated network within the Hyper-V environment.
The basic default configuration of a Hyper-V VM connects its network adapter to an external virtual switch, thus attaching the guest OS on the VM to the outside network. The VM can then take advantage of services running on the outside network and send traffic through routers to other networks, including the Internet.
This type of arrangement can enable administrators to consolidate many physical servers into VMs on a single Hyper-V server, providing them all with access to the entire network.
There is no distinction here between the physical network and the virtual one in the Hyper-V space.

Extending a production network into virtual space

Keep in mind that a Hyper-V server can have multiple physical network adapters installed in it, which might be connected to different networks to separate traffic or they might be connected to the same network to increase available bandwidth. You might also have adapters dedicated to SAN connections for shared storage and server clustering. Microsoft recommends the use of at least two physical network adapters in a Hyper-V server, with one adapter servicing the parent partition and the other connected to the child partitions. When you have more than two physical adapters in the server, you can create separate external virtual network switches for the physical adapters and connect each one to a separate VM.

Creating an isolated network

For testing and evaluation purposes or for classroom situations, administrators might want to create isolated network environments. By creating internal or private virtual switches, you can create a network that exists only within the Hyper-V space, with or without the parent partition included.
An isolated network such as this has limitations, however. If you want to install the guest OSs by using Windows Deployment Services or configure the VMs by using DHCP, you must install and configure those services on your private network. The guest OSs also do not have access to the Internet, which prevents them from downloading OS updates. In this case, you
must deploy appropriate substitutes on the private network.
One way to provide your systems with updates is to install two network adapters on each of your VMs, connecting one to a private switch and one to an external switch. This enables the VMs to access the Internet and the private network.
Another method for creating an isolated network is to use VLANs. This is particularly helpful if you have VMs on different Hyper-V servers that you want to add to the isolated network. By connecting the network adapters to an external switch and configuring them with the same VLAN identifier, you can create a network within a network, which isolates the VLAN from other computers. You can, for example, deploy a DHCP server on your VLAN without it interfering with the other DHCP servers in your production environment.

Thought experiment
Configuring Hyper-V networking
In the following thought experiment, apply what you’ve learned about this objective
to predict what steps you need to take. You can find answers to these questions
in the “Answers” section at the end of this chapter.
Ralph has a Windows Server 2012 R2 Hyper-V server with one physical network
adapter and one external virtual switch connected to that adapter. This arrangement
enables the VMs on the server to automatically download OS updates from
the Internet. However, Ralph wants to use the VMs on the Hyper-V server on an
isolated test network on which he can evaluate new software products. The test
network must have its own DHCP server that does not interfere with the DHCP
server on the production network.
How can Ralph create the test network he needs for his VMs without changing the
configuration that provides the machines with Internet access?

Objective summary
■■ Networking is a critical part of creating a VM infrastructure. Depending on your network plan, the VMs you create on a Windows Server 2012 R2 Hyper-V server can require communication with other VMs, with the computers on your physical network, and with the Internet.
■■ A virtual switch, like its physical counterpart, is a device that functions at Layer 2 of the OSI reference model. A switch has a series of ports, each of which is connected to a computer’s network interface adapter. Any computer connected to the switch can
transmit data to any other computer connected to the same switch.
■■ Hyper-V in Windows Server 2012 R2 supports three types of switches: external, internal, and private, which you must create in the virtual Switch Manager before you can connect VMs to them.
■■ Every network interface adapter has a MAC address—sometimes called a hardware address—that uniquely identifies the device on the network.
■■ Once you have created virtual switches in Hyper-V Manager, you can connect VMs to them by creating and configuring virtual network adapters.
■■ Selecting the Network Adapter option on the Add Hardware page creates what is known in Hyper-V terminology as a synthetic network adapter. Hyper-V supports two types of network and storage adapters: synthetic and emulated (sometimes called
legacy).
■■ NIC teaming is a Windows feature that enables administrators to join multiple network adapters into a single entity for performance enhancement or fault tolerance purposes.