MS WSL2-modified Linux kernel with ZFS support

Script to build the kernel from source

Syntax

./build.sh [ command [ arguments ] ]

Commands

update          # Update source code

clean           # Clean up source code

build           # Build kernel from source

install [ {KERNEL_TARGET_DIR} [ {KERNEL_SUFFIX} ] ]
                #
                # Install kernel to WSL2
                #
                # Optional arguments:
                #
                # - KERNEL_TARGET_DIR indicates the directory where the Kernel is stored on Windows
                #
                #       Default:  "C:\wsl2_zfs"
                #       Note:     Can be given as a Windows path, or WSL path.
                #
                # - KERNEL_SUFFIX specifies a suffix to be added to the resulting kernel-name:
                #       e.g. "kernel-5.15.90.1_zfs-2.1.9-1_SUFFIX.bin".
                #
                #       Default:  no suffix.
                #       Note:     This parameter requires KERNEL_TARGET_DIR to be set.
                #                 However, you can use "" if you still want to use the default value.

debs            # Install zfs command-line binaries to current distro

wslu            # Install/upgrade WSL Utilities command-line binaries to current distro

env             # Install building environment

help            # Show this help

info            # Show information about directories and source versions

version         # Show the script's version

Step-by-step instructions to build the kernel

1. For a fresh install, get the code:

   git clone https://github.com/multiheaded/zfs_on_wsl2.git && cd zfs_on_wsl2

   If you already have the repo, just run git pull to get any updates.
   
   

2. Get/update the WSL2-modified Linux kernel and OpenZFS source code:

   /bin/bash build.sh update

   Note: Should already set the WSL2-Linux-Kernel and zfs submodules under the 3rdparty directory to the correct tags. Verify and checkout fitting versions if necessary!
   
   

3. In case you had built the kernel before, first clean the source tree:

   /bin/bash build.sh clean

   WARNING: this will reset any changes you made under the 3rdparty/WSL2-Linux-Kernel and 3rdparty/zfs directories!
   
   

4. Start the build:

   /bin/bash build.sh

Result

• Kernel will be 3rdparty/WSL2-Linux-Kernel/arch/x86/boot/bzImage
• .deb files are created as 3rdparty/zfs/*.deb

Install the kernel to WSL

Option A: Automated install

1. Install the kernel and update .wslconf

   /bin/bash install

   Note: For more installation options, see the syntax of the install command above or in the ./build.sh help command output.
   
   

2. Install the zfs command-line utilities

   /bin/bash debs

   Warning: The installation of these binaries might fail due to missing dependencies or unresolved conflicts.
   Note: It is also possible to use the zfs binaries supplied by the package maintainers of your distribution.

Option B: Manual install

1. Install your newly built kernel by copying it to Windows:

   # Create a directory on "Windows" path to store the kernel
   mkdir -p /mnt/c/wsl2_zfs
   
   # Copy the Kernel file
   cp 3rdparty/WSL2-Linux-Kernel/arch/x86/boot/bzImage /mnt/c/wsl2_zfs/kernel

2. Also install the command-line utilities:

   sudo dpkg -i 3rdparty/zfs/zfs_*_amd64.deb 3rdparty/zfs/lib*.deb

3. In your Windows 10 environment, create or edit %userprofile%/.wslconfig and have it point to your kernel file. Copy and rename if necessary.

   [wsl2]
   kernel=c:\\wsl2_zfs\\kernel
   localhostForwarding=true
   swap=0

4. Start a PowerShell with administrator privileges, stop your WSL instances and restart LxssManager

   wsl --shutdown
   Restart-Service LxssManager

5. In your WSL2 environment, you should now be able to run

   sudo zfs version

   and get appropriate version information about ZFS.

Attach your drive with the ZFS partition to your WSL2 VM

To actually use it, check your drive paths from Powershell

wmic diskdrive list brief

and mount (bare) to WSL

wsl --mount \\.\PHYSICALDRIVE1 --bare

You can see that drive in Linux

lsblk

and zfs import {pool} or create a new pool from scratch.

Resources:

• https://wsl.dev/wsl2-kernel-zfs/
• https://docs.microsoft.com/de-de/windows/wsl/wsl2-mount-disk