Windows Server

Disk Deduplication: A great feature for lab environments

I have a reasonably powerful workstation that I’ve been using for testing and validation for many years, an HP z800 Workstation with 8 CPU cores, 96GB of RAM, and 4TB of disk space.  On that server, I have 55 VMs at the moment, including multiple ConfigMgr environments, MDT servers, Active Directory, proxy and VPN servers, clients of every SKU and version, etc.  At the moment, all of those VMs are on one 2TB SSD (because spinning disks are painful). 

But if you look at the volume with all of the virtual disks (VHDX’s) for all of those VMs, it’s not nearly full:


You can also see this via PowerShell:


That’s the great part of Disk Deduplication, a feature that has been available in Windows Server for quite some time, it enables you to save a lot of disk space.  You can follow the documentation for enabling this – it’s quite easy to do.  The basic steps:

  • Install the feature.
  • Configure it for each volume.  Basically, just turn it on and choose the workload type.  (I generally choose the “File server” workload type – to each his own.)

The deduplication process itself is handled through background processes.  If you want to be more aggressive at it (i.e. you want to free up disk space now because your drive is getting more full than you would like), you can use a script like Mikael Nystrom’s, which I do run periodically (usually when I find my ConfigMgr SUP is growing out of control).

The biggest negative for Disk Deduplication is that the feature is only available in Windows Server.  There is a uservoice item at to enable that in client OSes, and at one point we got very close to getting it into Windows 10 Pro for Workstations (which would mean it would be in Windows 10 Enterprise as well), but that effort fizzled  We’ve tried to stir that up via Twitter without much success either.  So make some noise: Add more votes to the uservoice item, submit requests via Feedback Hub, use social media.  Maybe one of these years…

Categories: Windows Server