Which of the following operating systems are supported for use within a generation 2 virtual machine?
A Generation 1 VM is a Microsoft Hyper-V virtual machine that uses the original Hyper-V BIOS-based architecture. Show
An example of retroactive nomenclature, the term Generation 1 VM came into use only after Microsoft introduced the Generation 2 VM format in Windows Server 2012 R2; prior to this release there was only one type of Hyper-V VM. Administrators using Windows Server 2012 R2 or later operating systems have the option of creating either type of VM. One of the primary differences between the two formats is that a Generation 1 VM was designed to closely emulate a physical machine, whereas a Generation 2 VM is hypervisor aware, and does not rely on synthetic or emulated hardware. For this reason, Generation 2 VMs often offer improved performance, such as faster boot times, than Generation 1 VMs. However, there are several reasons why administrators may choose to continue using Generation 1 VMs even in Windows Server 2012 R2 virtualization environments. For starters, VM generations cannot be changed once the VM is created. Therefore, if there's a chance a VM may need to be migrated to a server running an older version of Windows Server, then a Generation 1 VM would allow for this flexibility. Generation 1 VMs can access a physical DVD drive, whereas Generation 2 VMs cannot. Generation 2 VMs also only support Windows Server 2012 and later and 64-bit versions of Windows 8 and later as guest operating systems. Generation 1 VMs use the original VHD format, while Generation 2 VMs use the newer VHDX file format. This was last updated in February 2016 Continue Reading About Generation 1 VM (generation 1 virtual machine)
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Hyper-V Generation 1 vs. 2 – Which One to Choose?
There are two generations of Hyper-V virtual machines – Generation 1 and Generation 2. The choice of VM generation is important when a VM is created; this choice is also dependent on the guest operating system, the host operating system, boot methods and other factors. Generation 2 machines are newer than Generation 1 machines, although sometimes Generation 1 machines may be required for use. This blog post explains the differences between Hyper-V generation 1 vs 2 virtual machines, in order to help you make the right choice to meet your requirements. No matter which generation you choose, NAKIVO Backup & Replication can back up your Hyper-V VMs in a fast and reliable manner. Download the Free Edition of NAKIVO Backup & Replication now to keep your business data secure and consistent free of charge for an entire year. Hyper-V Generation 1 vs. 2: Characteristics of Gen 1 VMsBIOSBIOS is a Basic Input/Output System software that is flashed on a chip on a motherboard. BIOS is responsible for a machine’s start and hardware configuration. Gen 1 VMs support legacy BIOS-based architecture and can be loaded from MBR (Master Boot Record) virtual hard disks. A digital BIOS with virtual hardware is emulated by Hyper-V. IDE Virtual DisksGen 1 VMs have a virtual IDE controller that can be used for booting a VM from the IDE virtual disk. Virtual SCSI controllers can only be recognized after installing Hyper-V Integration Services on the guest OS on the VM. The guest OS cannot boot from a SCSI disk. Emulated HardwareA physical computer needs a set of hardware components in order to work. All required hardware components must be emulated to make the virtual machine work. Special software that can imitate the behavior of real hardware is included in Hyper-V; as a result the VM can operate with virtual devices. Emulated hardware (that is identical to real hardware) includes drivers that are catered to most operating systems in order to provide high compatibility. Among the virtual devices of Gen 1 VM you can find:
Hardware Limits of Gen 1 VMsThe hardware limits for Generation 1 VMs are:
Hyper-V Generation 1 vs. 2: Improvements of Gen2 VMsUEFI BIOS Support. GPT Support. Secure BootUEFI (Unified Extensible Firmware Interface) is low-level software that, similarly to BIOS, starts after powering on the computer ahead of loading the operating system (OS). The term “UEFI BIOS” is also used for better understanding. UEFI is not just a replacement of BIOS, UEFI extends support of devices and features. Some of these are GPT (GUID Partition Table) support and Secure Boot. GPT partitioning scheme allows one to overcome the limit of 2-TB disks for which the maximum number of partitions is 4 for a MBR partitioning scheme. Secure Boot is a feature that allows protection against modifying boot loaders and main system files; this is done by comparing the digital signatures that must be trusted by the Original Equipment Manufacturer (OEM). These features are available because Hyper-V Gen 2 VMs support UEFI. Boot from SCSI Virtual Disk. Native VMBUS SupportGen 2 VMs can be loaded from SCSI virtual disks because UEFI supports such communication with the SCSI controller while BIOS doesn’t. The support of synthetic VMBUS drivers for synthetic hardware during VM boot allows the use of SCSI drivers at the boot. For example, Gen 1 VMs can use only legacy IDE drivers for emulated devices before a file system is initialized. Hyper-V Integration Services must be installed to enable the SCSI controller for Gen 1 VMs. PXE Boot OptionBoth Gen 1 and Gen 2 VMs support a PXE (pre-boot execution environment), which is a network boot. However, there are some manual operations that should be done to enable a PXE boot for Gen 1 VMs. A synthetic network adapter that has higher performance is added to Gen 1 VM by default, but this type of network adapter doesn’t support a network boot for Gen 1 VMs. First shut down the VM and then add an emulated legacy network adapter. After this has been done you can use PXE boot for a Gen 1 VM. Gen 2 VMs support a network boot with a synthetic network adapter because they use UEFI, which is able to communicate with this network adapter type. Thus, you can use PXE boot for Gen 2 Hyper-V VMs without any additional tricks. VHDX Virtual DisksGen 2 VMs only support a VHDX format of virtual disk files while Gen 1 VMs support both VHD and VHDX formats. VHDX format has a list of advantages including:
Copying Files from Hyper-V Host to VMs without Network Connection of VMsThere is Enhanced Session Mode for Gen 2 VMs that uses a Remote Desktop Protocol. This feature allows the sharing of local resources of the Hyper-V host with VMs, or the performance of copy/paste operations between host OS and guest OS without a network connection between Hyper-V host and guest VM. File exchange can be performed with a Graphical User Interface (VM Connect) or PowerShell (Copy-VMFile cmdlet). Some requirements must be met:
As you can see, copying files becomes more convenient for Gen 2 VMs. For Gen 1 VMs, the only way of copying files from host OS to guest OS is copying files over the network. VMs Boot FasterThe boot time of Gen 2 VM is about 20% faster due to the faster start of the UEFI. Installation of a guest operating system also takes up to 50% less time. Although during regular use this advantage can be unnoticeable, it may help you save time when you need to install and configure a high number of new VMs or use Virtual Desktop Infrastructure (VDI). Fewer Devices, Synthetic HardwareIn the past, operating systems were released without the awareness of running on virtual machines. For this reason, hardware emulation is used. Gen 1 VMs use the approach of hardware emulation for maximum compatibility. The newest operating systems are aware of running on virtual machines and use VMBus instead of searching legacy controllers or chipsets. Most of the legacy-emulated devices have been removed for Gen 2 VMs, and new faster synthetic hardware is used instead. With tighter hypervisor integration and a lower number of virtual devices, VM performance may increase. Higher CPU and RAM LimitsThe maximum amount of virtual RAM and the maximum number of virtual CPU that can be assigned for a virtual machine has been increased: 1 TB RAM for Generation 1 VMs vs 12 TB RAM for Generation 2 VMs; 64 virtual processors for Generation 1 VMs vs 240 virtual processors for Generation 2 VMs. Thus, you can use Gen 2 VMs for tasks that consume more resources. Before creating the VM, check if the version of the host operating system supports the required maximum amount of memory and maximum number of virtual processors. Windows Server 2016 has higher limits than Windows Server 2012 R2. Data Protection with NAKIVO Backup & Replication Designed for businesses of all sizes, NAKIVO solution offers complete data protection for all of your production workloads, including VMware vSphere Backup, Hyper-V Backup, Microsoft 365 Backup and more. Get the Free Trial now! Hyper-V Generation 1 vs. 2: Requirements for Gen2 VMsGeneration 2 VMs have been released by Microsoft with Hyper-V for Windows Server 2012 R2 and Windows 8.1; hence these versions of 64-bit Windows (or later, including standalone Hyper-V Server 2012 R2) are required on the Hyper-V host for running Gen 2 VMs. Guest operating systems for Gen 2 VMs can be Windows Server 2012 or later Windows Server versions, Windows 8 x64 or above because of the support of UEFI 2.3.1 with Secure Boot option. Hyper-V Generation 1 vs. 2: Advantages of Using Gen2 VMsLet’s summarize the main advantages of using Gen 2 VMs. Gen 2 VMs provide:
Gen 2 VMs are recommended to use in most cases, especially for modern 64-bit operating systems. ExceptionsThere are exceptions, when the Gen1 VM is preferable over Gen2 VM:
How to Create a Gen1 VM and Gen2 VM?To create a virtual machine in GUI:
When the generation has been selected, click “Next” and configure other options in the wizard to finish creating the VM. How to Convert a Gen2 VM to Gen1 VM and Vice Versa?Microsoft doesn’t provide any tools for converting VMs from one generation to another. As a proof of this you can see a warning on the screenshot above: “Once a virtual machine has been created, you cannot change the generation”. Try to predict any possible use cases for the VM before creation, because changing a VM generation afterwards is not supported. However, there is one unofficial tool for converting Gen 1 VMs to Gen 2 VMs which is called Convert-VMGeneration. This tool doesn’t modify the source Gen1 VM. A new Gen 2 VM with a new boot disk is created during conversion process. You can use this tool at your own responsibility without any warranties. Backup of Hyper-V VMsDespite the generation of VMs, they should be backed up to prevent the data loss. NAKIVO Backup & Replication can back up both generations of Hyper-V virtual machines and provides the following features:
ConclusionToday’s blog post has covered two generations of Hyper-V virtual machines - Generation 1 and Generation 2. The Gen 2 VMs are more progressive because they use synthetic virtual devices, UEFI BIOS, GPT partitioning scheme, Secure Boot, PXE boot without tricks, more reliable VHDX virtual disks, and have higher hardware limits. Gen 2 VMs are preferred for use, but only 64-bit operating systems can run on them. If you need to run older operating system or 32-bit operating system, then use Gen
1 VMs which have legacy emulated virtual devices, BIOS, support of COM ports, virtual floppy disks, virtual IDE controllers, and attached physical DVD drives. It is important to try to predict all possible use cases before you create the VM because changing the generation of the VM after creation is not supported. What is a Generation 2 virtual machine?Generation 2 virtual machines have a simplified virtual hardware model, and supports Unified Extensible Firmware Interface (UEFI) firmware instead of BIOS-based firmware. The majority of legacy devices have also been removed from generation 2 virtual machines.
What operating systems does an Azure virtual machine support?Supported Operating Systems for Azure. Which operating system can be operated on a VM?Virtual Machine Programs
Some options are VirtualBox (Windows, Linux, Mac OS X), VMware Player (Windows, Linux), VMware Fusion (Mac OS X) and Parallels Desktop (Mac OS X). VirtualBox is one of the most popular virtual machine programs since it is free, open source, and available on all the popular operating systems.
What extension is used for a generation 2 virtual machine image?Generation 2 virtual machines only support VHDX format virtual hard drives. You can convert VHD files to VHDX format using the Edit Virtual Hard Disk Wizard in the Hyper-V Manager console or use the Convert-VHD Windows PowerShell cmdlet.
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