Lets get the disclaimer out of the way first: What I’ve done is absolutely unsupported by Microsoft. Just because it works for me does not guarantee it will work for you and I am not in any way recommending that you follow my lead!
I use a great many virtual machines for both customer work, internal projects and just tinkering. My ThinkPad X220T is tricked out with extra RAM and two SSDs. Space is still an issue, though, and I can’t squeeze any more storage into my little workhorse.
Windows Server 2012 introduced Data Deduplication – a fantastic feature that is saving us huge amounts of disk space on our SCVMM library. I’d love to be able to use that on Windows 8.1 Sadly, Microsoft didn’t see fit to enable the feature.
There are a good many people out there who thought like I do and some of them decided to to figure out how to get data deduplication working on Windows 8.1. I’m not going to repeat those instructions here – I will instead post a link to the best of the articles I read before taking the leap, that of Mike Bijl.
Having installed and enabled the Data Deduplication feature I enabled dedupe on my D drive – a 500Gb Crucial M500 SSD. Note that you cannot dedupe your OS partition – you need OS and data volumes to get anywhere with this process. I started with about 12Gb of free space, gobbled up by ISO files and VHDs of installed VMs. Those dedupe beautifully, and I now have 245Gb of free space.
Have I encountered any problems yet? No. All my VMs run fine. I have a scheduled dedupe job running at noon to keep things tidy that has given no problems so far.
It is important to reiterate Mike’s point, however: If you enable dedupe on a volume and reinstall Windows 8.1 you will not be able to access any data on the drive until you re-enable dedupe (or stick the volume in a Windows Server 2012 or 2012 R2 machine). I’m happy with that – it’s no big deal for me. I would not, however, allow any of our developers to do this on their workstations, for example.
Doing all this, however, has got me thinking… Homegroup support is missing from Server 2012 and 2012 R2. I wonder if the same process might be used to enable features in the opposite direction…?