Accelerated Networking seems disabled when creating vm from disk

Question

I created a vm with Windows Server 2019 x64. I selected Accelerated Networking is enable when it is creating.
After I created a snapshot from this instance I created disk from the snapshot. When I want to create Vm from disk, Accelerated Networking option is coming disabled. I want to use Accelerated Networking and I try to enable it but getting a this warning.
"Network connectivity will be interrupted if the operating system of your virtual machine does not support accelerated networking. Disable accelerated networking if connectivity to your virtual machine is interrupted."

What do you recommend this situation? I didn't get it this problem, Shouldn't it support the Accelerated Networking option?

Answer 1

Hello @emre sevinc
The reason why your VM, that is created from disk have Accelerated Networking option disabled is that Accelerated Networking is the feature of NIC and should be created on network interface.
So when you created new VM from snapshot, you got new NIC without enabled Accelerated Networking by default.
To create NIC with Accelerated Networking you may use script

az network nic create \
    --resource-group myResourceGroup \
    --name myNic \
    --vnet-name myVnet \
    --subnet mySubnet \
    --accelerated-networking true \
    --public-ip-address myPublicIp \
    --network-security-group myNetworkSecurityGroup

Windows Server 2019 x64 supports Accelerated Networking but there are some prerequisites and limitations:

• Accelerated Networking is supported on most general purpose and compute-optimized instance sizes with 2 or more vCPUs. On instances that support hyperthreading.
• Accelerated Networking is supported on VM instances with 4 or more vCPUs.
• Although NC and NV sizes will show in the command below, they do not support Accelerated Networking. Enabling Accelerated Networking on NC or NV VMs will have no effect.
• A supported VM size without accelerated networking enabled can only have the feature enabled when it's stopped and deallocated.

[https://learn.microsoft.com/en-us/azure/virtual-network/accelerated-networking-overview#supported-vm-instances

The list of Virtual Machine SKUs that support Accelerated Networking can be queried directly via the following Azure CLI
az vm list-skus --location westus --all true --resource-type virtualMachines --query '[].{size:size, name:name, acceleratedNetworkingEnabled: capabilities[?name==`AcceleratedNetworkingEnabled`].value | [0]}' --output table