I need to upgrade Standard "D8s v3 (8 vcpus, 32 GiB memory)" to same number of vCPUs and 64GB RAM

Hi Ankit,

Urgent family issues prevented me from doing this abut I am just now revising it and a crucial question came to my mind.

You write :

• 1. The guest OS (Windows Server 2019) will typically detect the updated CPU and memory automatically

1. In most cases, nested virtualization (Hyper-V) continues to function without additional configuration, provided the new VM size supports it

My experience of doing physical resizing of a VM host, etc..., is that the most critical part is not so much the CPU and memory, but the network adapter because, in the physical world, that network adapter changes and that in turn destroys all port forwarding rules because one has to re-do all the Powershell commands (e.g. Add-NetNatStaticMapping) to do port forwarding to the nested VMs, and that's a lot of work and testing work.

In this case we have over a dozen port forwarding rules to the nested VMs- so will upgrading the server destroy all these because the network adapter name will change ? In other words is the resizing, from the Azure VM standpoint, purely a vCPU and RAM change, or does it extend to the virtual network adapter ?

M.

Hi @HCML TEST,

Thank you for posting you query, based on your requirements (8 vCPUs, 64 GiB memory, and nested virtualization support), here is how you can approach this:

#1 Supported VM options for nested virtualization

Nested virtualization in Azure is supported on specific VM series where CPU virtualization extensions are exposed to the guest OS. This includes:

• Dv3, Dv4, Dv5 series
• Ev3, Ev4, Ev5 series

Since you are looking for 8 vCPUs and 64 GiB RAM, the following are appropriate options:

• E8s_v3, E8s_v4, E8s_v5 – these meet your memory requirement and support nested virtualization
• D8s_v4 or D8s_v5 – these also support nested virtualization, but they provide 32 GiB RAM, so they would not meet your 64 GiB requirement

From this, E-series SKUs are the correct upgrade path if 64 GiB memory is required.

Note: Before proceeding, we recommend confirming:

• The selected VM size is available in UK South region
• Your subscription has sufficient quota for the Ev family*

#2 Behavior after resizing the VM

Before resizing as a precaution, since the Dv3 family provides temporary storage, please move your data from the temporary disk to the OS disk or any attached disk. Also, take a snapshot of the OS disk to ensure your data is backed up in case of any issues.

To resize:

1. Stop (deallocate) the VM
2. Change the VM size
3. Start the VM again

After resizing:

• The guest OS (Windows Server 2019) will typically detect the updated CPU and memory automatically
• In most cases, nested virtualization (Hyper-V) continues to function without additional configuration, provided the new VM size supports it

However, it is important to note:

• Azure does not guarantee completely seamless transitions across all scenarios
• We recommend validating inside the VM after resize:
  • Hyper-V role remains enabled
  • Nested VMs start successfully

References:

• https://learn.microsoft.com/en-us/windows-server/virtualization/hyper-v/nested-virtualization
• https://learn.microsoft.com/en-us/azure/virtual-machines/sizes/general-purpose/dsv3-series?tabs=sizebasic
• https://learn.microsoft.com/en-us/azure/virtual-machines/sizes/memory-optimized/ev4-series?tabs=sizebasic

a) From the provided information, nested virtualization support is explicitly documented for:

• ECesv6-series (up to 64 vCPUs, 512 GiB RAM) – this series supports Nested Virtualization and offers sizes with 8 vCPUs and higher memory (for example, Standard_EC8es_v6 has 8 vCPUs and 64 GiB RAM).

So, for an 8 vCPU / 64 GiB configuration with nested virtualization, Standard_EC8es_v6 in the ECesv6-series is a documented option.

Note: Mdsv3 Very High Memory sizes explicitly do not support Nested Virtualization, so they are not suitable for this scenario.

b) The context only provides generic resize guidance and does not describe any required in-guest reconfiguration steps specific to nested virtualization when resizing. It only states that:

• To change VM size, choose a new size and then resize the VM.

No additional in-guest reconfiguration requirements are documented in the provided material.

References:

• ECesv6 series
• Mdsv3 Very High Memory sizes series
• Migrate your HBv2-series virtual machines by May 31, 2027