Last week, I reported that I was planning to move Windows from an SSD to an HDD. My main reason was that I wanted to free the small 128 SSD on this HP’s i7 laptop for Hyper-V differencing parent disks, while installing Windows onto the bigger 1 TB HDD. Also those virtual machine child disks would (and could) be installed on the HDD; as the parent disk would be on an SSD, it greatly impacts the speed of a virtual machine. I was not worried about longer boot times when Windows runs on an HDD instead of an SSD, losing a minute or two in boot time is about as irrelevant to me as alcohol-free beer.
I fought with the Windows Insider Fast Ring upgrade over the whole weekend, failing each and every install attempt, whatever I tried. I will write a war story about those adventures later. For now, it’s enough to say that I decided to forget the upgrade and deploy a fresh Insider Fast build 18975 image. I customized my image in MDT, and deployed it yesterday (Sunday). The whole SSD is now reserved for differencing parent disks, and Windows now resides on the HDD.
I created my first three parent disks this morning:
I use each and every version-specific parent VHD for four different virtual machines, each with a different language (English, Finnish, Swedish and German). When I create a parent VHD, I always use the English install media. I stop when OOBE starts and shows the region selection screen. Opening Command Prompt with SHIFT + F10, and immediately closing it activates the WIN-key shortcuts in OOBE, and changes the Ease of Access button (bottom left) to the Settings button. I open Settings, install Finnish, Swedish and German language packs, and run Windows Update to fully update Windows:
When that’s done, I press WIN + E to open File Explorer, browse to %windir%\System32\Sysprep folder and run Sysprep, The, I shut each VM down when Sysprep is done.
When I then create a new VM with a child disk using this prepared parent disk and boot it, in less than a minute it shows me this screen:
In this example I selected Svenska (Swedish) and, although the parent disk has English Windows 10, the Windows display language on this virtual machine’s child disk will be completely changed to Swedish:
I am happy that I decided to move Windows from the small SSD to the bigger HDD. Not caring if Windows boots now a bit slower, I reached my main goal: my virtual machines are faster when the Windows base installation on a differencing parent disk is on the SSD. From 119 GB of usable disk space on the SSD, I have now the three first Windows 10 parent disks (Slow, Fast and GA versions), and can use each of them to install in four different languages to four different virtual machines. And, I still have enough space on that SSD to store Windows 7 & 8, and Windows 10 Enterprise parent disks on it.
Each new VM using a child disk saves me over 10 GB of storage space, the size of Windows 10 base installation before any user data. Windows on Hyper-V differencing disks loads the OS from the parent disk, and the child disk only contains user data and settings. Using my Fast Ring Insider virtual machines as an example, I saved over 33 GB of storage space on the HDD (4*11 GB on each VM with child VHD – parent’s 11 GB). That’s the main reason why I as a Hyper-V enthusiast use differencing disks, and the main reason for moving Windows from the SSD to the HDD to make my virtual machines faster.
I really do not care that my boot time went from about 30 seconds to a minute and a half (plus an additional minute for Windows to be fully functional). I do not care that my restart time went from about a minute to almost two and a half minutes:
I do not boot or restart often, usually less than once a day not counting restarts required by software installation or Windows Update. Other than those mentioned boot and restart times, I have no issues. Windows runs fast enough for me.
Now to work, I still have space available on my SSD for Windows 7, Windows 8 and Windows 10 Enterprise parent disks! I will now go build some.
Author: Kari Finn
A former Windows Insider MVP, Kari started in computing in the mid 80’s writing code for VAX / VMS systems. Since then, he’s worked in a variety of IT positions. He specializes in Windows image capture, customization, repair and deployment as well as Hyper-V virtualization. Kari is a proud Team Member at number #1 Windows site TenForums.com.