More experimenting with RAMdisks: Using a VM completely in RAM

In my previous post, I talked about using a small RAMdisk to speed up the process of generating MDT boot images.  But the trial version only supports RAMdisks up to 4GB in size and only on client OSes.  One comment posted to that blog pointed out that StarWind also has a free RAMdisk available, and it supports larger RAMdisks and server OSes.  See for more information.  (Again, I’m not recommending it, just pointing out its existence.  Registration is required to download.)

This let me test out another scenario: Creating a RAMdisk large enough to hold an entire virtual machine, then seeing how much faster Windows can be deployed into such a virtual machine.  Fortunately, I have a workstation-class machine with enough RAM to do something like that.  I created a 20GB RAMdisk, formatted it as NTFS, then created a new VM where the VHDX file (using Windows Server 2012) was on the RAMdisk.

Using a physical disk array (attached to an Intel RAID controller) on the same system, I can deploy Windows 8 in about 10 minutes (new computer, clean install, no apps, no updates, etc.).  So how much faster is the RAMdisk?  On my machine, it took about eight minutes – noticeable, shaving 20% off of the time, but not as fast as I would have hoped.  That’s another case of shifting the bottleneck: the image is pulled across the (virtual) network, read from a physical disk (VHD), consumes CPU, etc.  Now if I only had enough RAM to load my entire server VHD into a RAMdisk to see what that does.  Last time I checked, the server required about a terabyte of disk space, so going that far is not possible.

But I can do the next best thing:  Create an MDT media ISO, copy that into the RAMdisk, and do a deployment using that instead of over the network.  How long did take?  About 7 minutes and 30 seconds.  Sigh, 30 seconds saved.

One more test:  Give the VM more CPUs.  Instead of the default single core, I increased it to four cores and tried again.  This time, the deployment completed in 6 minutes and 30 seconds.  Another minute shaved off.  (Don’t have lots of RAM?  Well, you probably have more than one CPU in your Hyper-V server, use it when building images.)

So that’s up to a 35% improvement in performance – good overall, but not quite the fantastic results I was hoping for.  Ah well, it was worth a try…

Comments (8)
  1. Anonymous says:

    How about trying some different ram disk software. Google ram disk comparison and top is a review of 12 different ones. Try the free one with the highest 4k write. Also just create a new deployment share on a separate ramdisk.

  2. Christiaan Ghijselinck says:

    NTFS consumes rather intensively CPU type.  The exFAT filesystem would be a better choice for the ramdisk where the VHD are stored. The Qsoft ramdisk supports exFAT , even without an additional format run.

  3. Gabe Ster says:

    Thank you for posting this - I only discovered it today but have wondered just how much a fully-in-RAM solution would benefit image build/deployment times. Not as much as I'd hoped either... but you've saved me a bunch of time testing it myself to find out.

  4. anon says:

    you can look for imdisk, which is free and let you create ramdisks of any size

  5. showbox says:

    Thanks for the great info. I really loved this. I would like to apprentice at the same time as you amend your web site, how could i subscribe for a blog site?
    For more info on showbox please refer below sites:
    Latest version of Showbox App download for all android smart phones and tablets. - It’s just 2 MB file you can easily get it on your android device without much trouble. Showbox app was well designed application for android to watch movies and TV shows, Cartoons and many more such things on your smartphone.
    For showbox on iOS (iPhone/iPad), please read below articles:
    Showbox for PC articles:
    There are countless for PC clients as it is essentially easy to understand, simple to introduce, gives continuous administration, effectively reasonable. it is accessible at completely free of expense i.e., there will be no establishment charges and after establishment
    it doesn't charge cash for watching films and recordings. Not simply watching, it likewise offers alternative to download recordings and motion pictures. The accompanying are the strides that are to be taken after to introduce Showbox application on Android.
    The above all else thing to be done is, go to the Security Settings on your Android telephone, Scroll down and tap on 'Obscure sources'.

  6. Jaiyan says:

    I just want you to know that was a great project to be part of you've done on your site – captivating stuff.

  7. aw says:

    hai, I just want to tell you that I am just very new to blogs and seriously loved this website. More than likely I’m planning to bookmark your blog post .
    You amazingly come with really good posts. Thanks a lot for sharing your blog Microsoft.

Comments are closed.

Skip to main content