dev-manual: add instructions for compacting WSLv2 VHDX files

Using DiskPart for the systems which lack optimize-vhd

(From yocto-docs rev: c692b77065e6bd8eda789a88fa8fae1351a7274d)

Signed-off-by: Tony McDowell <svet.am@gmail.com>
Reviewed-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 30 insertions, 11 deletions

diff --git a/documentation/dev-manual/start.rst b/documentation/dev-manual/start.rst
index 9c7dde8cf2..701d3cf4dc 100644
--- a/documentation/dev-manual/start.rst
+++ b/documentation/dev-manual/start.rst
@@ -502,9 +502,10 @@ your Yocto Project build host:
    can be easily avoided by manually optimizing this file often, this
    can be done in the following way:
 
-   1. *Find the location of your VHDX file:* First you need to find the
-      distro app package directory, to achieve this open a Windows
-      Powershell as Administrator and run::
+   1. *Find the location of your VHDX file:*
+
+      First you need to find the distro app package directory, to achieve this
+      open a Windows Powershell as Administrator and run::
 
          C:\WINDOWS\system32> Get-AppxPackage -Name "*Ubuntu*" | Select PackageFamilyName
          PackageFamilyName
@@ -516,22 +517,40 @@ your Yocto Project build host:
       replace the PackageFamilyName and your user on the following path
       to find your VHDX file::
 
-          ls C:\Users\myuser\AppData\Local\Packages\CanonicalGroupLimited.UbuntuonWindows_79abcdefgh\LocalState\
-          Mode                 LastWriteTime         Length Name
-          -a----         3/14/2020   9:52 PM    57418973184 ext4.vhdx
+         ls C:\Users\myuser\AppData\Local\Packages\CanonicalGroupLimited.UbuntuonWindows_79abcdefgh\LocalState\
+         Mode                 LastWriteTime         Length Name
+         -a----         3/14/2020   9:52 PM    57418973184 ext4.vhdx
 
       Your VHDX file path is:
       ``C:\Users\myuser\AppData\Local\Packages\CanonicalGroupLimited.UbuntuonWindows_79abcdefgh\LocalState\ext4.vhdx``
 
-   2. *Optimize your VHDX file:* Open a Windows Powershell as
-      Administrator to optimize your VHDX file, shutting down WSL first::
+   2a. *Optimize your VHDX file using Windows Powershell:*
+
+       To use the ``optimize-vhd`` cmdlet below, first install the Hyper-V
+       option on Windows. Then, open a Windows Powershell as Administrator to
+       optimize your VHDX file, shutting down WSL first::
 
          C:\WINDOWS\system32> wsl --shutdown
          C:\WINDOWS\system32> optimize-vhd -Path C:\Users\myuser\AppData\Local\Packages\CanonicalGroupLimited.UbuntuonWindows_79abcdefgh\LocalState\ext4.vhdx -Mode full
 
-      A progress bar should be shown while optimizing the
-      VHDX file, and storage should now be reflected correctly on the
-      Windows Explorer.
+       A progress bar should be shown while optimizing the
+       VHDX file, and storage should now be reflected correctly on the
+       Windows Explorer.
+
+   2b. *Optimize your VHDX file using DiskPart:*
+
+       The ``optimize-vhd`` cmdlet noted in step 2a above is provided by
+       Hyper-V. Not all SKUs of Windows can install Hyper-V. As an alternative,
+       use the DiskPart tool. To start, open a Windows command prompt as
+       Administrator to optimize your VHDX file, shutting down WSL first::
+
+         C:\WINDOWS\system32> wsl --shutdown
+         C:\WINDOWS\system32> diskpart
+
+         DISKPART> select vdisk file="<path_to_VHDX_file>"
+         DISKPART> attach vdisk readonly
+         DISKPART> compact vdisk
+         DISKPART> exit
 
 .. note::