Azure and uploading OS VHD´s larger than 127 GB

I have been busy with a newborn baby and not had so much time over for my blog but now I am back at work 🙂

I was reading this post about how to convert the vhdx to vhd before uploading your virtual disks to Azure and felt that I needed to explore why the default OS vhd disks on the IaaS role is 127 GB and not larger. There was once a limit that Virtual PC could not utilize larger disks than 127GB on the IDE controller but do not think that Azure runs on Virtual PC 😉

In your local cloud and Hyper-V 2012 you can create VM´s with OS disks connected to the IDE that is larger than 127 GB, although the best practice is to create additional disks and connect them to the SCSI controller instead and install the services there!

So to test first that i could convert a vhdx to vhd and then upload it, and also be able to use it in Azure I used the Convert-WindowsImage.ps1 script to create my test-vm that was 128GB large.

Screen Shot 2013-09-09 at 16.06.56

When uploading with the cmdlet from the Azure PowerShell module it goes quite fast as it only uploads the bits that contains data, not empty blocks.

Screen Shot 2013-09-09 at 15.07.44

And when the upload is finished you create a disk from the uploaded VHD, and as you can see on the screendump it is still 128 GB

Screen Shot 2013-09-09 at 15.16.18

and when I start and connect to it, it show the disk size of 128 GB inside the IaaS VM also!

Screen Shot 2013-09-09 at 15.35.26

One lesson learned is that before uploading your own virtual machine VHD to Azure, and that is to enable remote desktop settings as otherwise you will not be able to connect to the Azure virtual machine once it is running.

Screen Shot 2013-09-09 at 15.53.06


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