[jbell]

In Windows Server 2008 R2 the default size for a Hyper-V virtual disk seems to be 127GB. I implemented a virtual machine that is being used as a domain controller, and missed the default size setting. It has been in production for quite some time. I now really need the excess disk space and would like to reduce the virtual hard drive size to about 50% of what it currently is.

Is there a safe way to do this? I see lots on how to expand drives, but little on reducinig their size. And the few posts I have seen on that seem risky. Since this is a domain controller I really do not want to take any big risks.

Thanks for any help you may be able to offer.

BTW, I know that it is theoretically possible to back up the entire VM, then create a new, empty drive and restore the backup into it. However, I have been cautioned that this can be quite risky with domain controllers.

Thanks again,

Jeff Bell

[Virtual]

I would be tempted to build another VM alongside, make it a DC and then transfer roles to it.

The default VHD is a Dynamic disk. Double check what space is being taken up by the VM. Ensure you take a system state backup of the VM when logged in including the VM files itself. If it is a fixed disk, you could consider converting the VHD to a Dynamic. However, I tend to defragment the drive prior to doing so and as you already mention, can carry risks.

[biggles77]

Haven't tried shrinking a VHD of the system drive on a DC so I don't know if VHDResizer will work on it or not. Still a useful tool to have if it doesn't.

[Virtual]

Come to think of it and as already mentioned, I would personally just create another DC and transfer roles to it, you can defragment the current Windows system within the VHD and using the Edit Disk tool to then Compact the VHD to free up the space taken up by white space. If it is a fixed disk, you can then consider converting it to a Dynamically Expanding VHD.