Dev Drive is Now Available

Erik Mavrinac

October 13th, 20233 4

(Edited Oct 31, 2023 to add info about later patch for InTune, Nov 6 and 8, 2023 to add Win11 23H2 image info, and Apr 4, 2024 to add info about Server. Also see the next post.)

In a previous post, Dev Drive and Copy-on-Write for Developer Performance, we published early performance numbers for the new Dev Drive feature of Windows 11 and Windows Server. This week’s Windows Update for Windows 11 22H2 includes Dev Drive and you can check by running the command format /? and seeing if the /DevDrv parameter is listed in the help text.

If Dev Drive doesn’t appear in the help text, you can explicitly enable it by installing the additional Windows patch, KB5030509 for both Windows 11 22H2 and 23H2. To install the patch:

  1. Open Windows Update,
  2. Turn on the Get the latest updates as soon as they’re available option¹
  3. Install the update listed
  4. Reboot.

Once enabled, follow these setup instructions to create and format a Dev Drive volume.

If your company or organization is using InTune management you should also install the follow-up optional OS release KB5031455, “2023-10 Cumulative Update Preview for Windows 11.”

Since the last post, we continued to add more copy-on-write functionality to MSBuild: This includes an updated Microsoft.Build.Artifacts SDK to add CoW linking and several bug fixes to Microsoft.Build.CopyOnWrite.

We also continue to roll out copy-on-write for more repos inside Microsoft. In a recent win we reduced build time for a large C# repo by 16% after updating to the newer Artifacts SDK and adding the CopyOnWrite SDK, then moving to Dev Drive.

Dev Drive was not backported to Windows Server 2022, but it will be in the next major release.

¹ Return to normal patch rollouts by disabling the update option after rebooting.

Erik Mavrinac Principal Software Engineer, 1ES Engineering

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3 comments

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  • Alex Ivanoff 0

    Is it possible to “create” Dev Drive on Windows 10 by manually formatting the drive as ReFS and making some other changes?

    • Erik MavrinacMicrosoft employee 0

      No, this functionality is only built into Windows 11.

  • Jeremy Powell 0

    I think one option that’s missing from the instructions/GUI is to reformat an existing drive for DevDrv. I hope the following is roughly equivalent:

    format D: /fs:ReFS /DevDrv /Q

    The GUI approach takes an age to process the available volumes for some reason too…

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