Can we use dynamically expanding disk to create a VM in azure?

Question

I have created a VM in hyperv using dynamically expanding VHD option.Now I have exported that VHD to azure cloud and created a VM in azure.My VM is not booting properly. Is it recommended to use dynamically expanding VHD to create VM in azure?

Answer 1

OS and Data disks (ephemeral storage is local to the hardware) are thin provisioned in Azure. That is they are dynamically expanding. This is a decision made by Azure (so they don't have to store hundreds of thousands of mostly empty 120gb C: drives, which also makes it cheaper for you. ) and there is no option to change that.

Disks that you upload need to be a fixed size. (so you will pay for the full size)

According to Azure Documentation - Upload a Windows VM image to Microsoft Azure for Resource Manager deployments

Microsoft Azure can only accept images for Generation 1 virtual machines saved in the VHD file format. The VHD size must be fixed and a whole number of MB. The maximum size allowed for the VHD is 1023GB.

If you are having problems with an uploaded disk, it is likely that the problem is that you have created a dynamically expanding one and it simply isn't booting.

Answer 2

Usually, you want to create the VM with a fixed size disk as the dynamically expanding disks have a performance cost.

More information here: https://technet.microsoft.com/en-us/magazine/ff458359.aspx