Support for generation 2 VMs (preview) on Azure
Support for generation 2 virtual machines (VMs) is now available in preview in Azure. You can't change a virtual machine's generation after you've created it, so review the considerations on this page before you choose a generation.
Generation 2 VMs support key features that aren't supported in generation 1 VMs. These features include increased memory, Intel Software Guard Extensions (Intel SGX), and virtualized persistent memory (vPMEM). Generation 2 VMs also have some features that aren't supported in Azure yet. For more information, see the Features and capabilities section.
Generation 2 VMs use the new UEFI-based boot architecture rather than the BIOS-based architecture used by generation 1 VMs. Compared to generation 1 VMs, generation 2 VMs might have improved boot and installation times. For an overview of generation 2 VMs and some of the differences between generation 1 and generation 2, see Should I create a generation 1 or 2 virtual machine in Hyper-V?.
Generation 2 VM sizes
Generation 1 VMs are supported by all VM sizes in Azure. Azure now offers preview generation 2 support for the following selected VM series:
- Dsv2-series and Dsv3-series
- Ls-series and Lsv2-series
- NCv2-series and NCv3-series
Generation 2 VM images in Azure Marketplace
Generation 2 VMs support the following Marketplace images:
- Windows Server 2019 Datacenter
- Windows Server 2016 Datacenter
- Windows Server 2012 R2 Datacenter
- Windows Server 2012 Datacenter
On-premises vs. Azure generation 2 VMs
Azure doesn't currently support some of the features that on-premises Hyper-V supports for generation 2 VMs.
|Generation 2 feature||On-premises Hyper-V||Azure|
|Virtualization-based security (VBS)||✔️||❌|
Features and capabilities
Generation 1 vs. generation 2 features
|Feature||Generation 1||Generation 2|
|VM sizes||All VM sizes||Only VMs that support premium storage|
Generation 1 vs. generation 2 capabilities
|Capability||Generation 1||Generation 2|
|OS disk > 2 TB||❌||✔️|
|Custom disk/image/swap OS||✔️||✔️|
|Virtual machine scale set support||✔️||✔️|
|Shared image gallery||✔️||❌|
|Azure disk encryption||✔️||❌|
Creating a generation 2 VM
In the Azure portal or Azure CLI, you can create generation 2 VMs from a Marketplace image that supports UEFI boot.
windowsserver-gen2preview offer contains Windows generation 2 images only. This packaging avoids confusion between generation 1 and generation 2 images. To create a generation 2 VM, select Images from this offer and follow the standard process to create the VM.
Currently, Marketplace offers the following Windows generation 2 images:
See the Features and capabilities section for a current list of supported Marketplace images.
Managed image or managed disk
You can create a generation 2 VM from a managed image or managed disk in the same way you would create a generation 1 VM.
Virtual machine scale sets
You can also create generation 2 VMs by using virtual machine scale sets. In the Azure CLI, use Azure scale sets to create generation 2 VMs.
Frequently asked questions
Are generation 2 VMs available in all Azure regions?
Yes. But not all generation 2 VM sizes are available in every region. The availability of the generation 2 VM depends on the availability of the VM size.
Is there a price difference between generation 1 and generation 2 VMs?
How do I increase the OS disk size?
OS disks larger than 2 TB are new to generation 2 VMs. By default, OS disks are smaller than 2 TB for generation 2 VMs. You can increase the disk size up to a recommended maximum of 4 TB. Use the Azure CLI or the Azure portal to increase the OS disk size. For information about how to expand disks programmatically, see Resize a disk.
To increase the OS disk size from the Azure portal:
- In the Azure portal, go to the VM properties page.
- To shut down and deallocate the VM, select the Stop button.
- In the Disks section, select the OS disk you want to increase.
- In the Disks section, select Configuration, and update the Size to the value you want.
- Go back to the VM properties page and Start the VM.
You might see a warning for OS disks larger than 2 TB. The warning doesn't apply to generation 2 VMs. However, OS disk sizes larger than 4 TB are not recommended.
Do generation 2 VMs support accelerated networking?
Yes. For more information, see Create a VM with accelerated networking.
Is VHDX supported on generation 2?
No, generation 2 VMs support only VHD.
Do generation 2 VMs support Azure Ultra Disk Storage?
Can I migrate a VM from generation 1 to generation 2?
No, you can't change the generation of a VM after you create it. If you need to switch between VM generations, create a new VM of a different generation.