Creating and Maintaining a VHDX Drive in WSL

This guide explains how to create, mount, and maintain a VHDX drive for use with WSL (Windows Subsystem for Linux).

Prerequisites

• Windows 10/11 with WSL2 installed
• Administrative access
• PowerShell
• Sufficient disk space

Creating the VHDX

1. First, check existing devices in your WSL distribution:

ls /dev/sd* -la

2. Create the VHDX file in PowerShell (run as Administrator):

New-VHD -Path "Z:\Disks\wsl-ubuntu-2404\data_disk.vhdx" -SizeBytes 500GB -Dynamic
wsl --mount --vhd "Z:\Disks\wsl-ubuntu-2404\data_disk.vhdx" --bare

Setting Up the Drive in WSL

1. Identify the new device:

ls /dev/sd* -la

Note: Compare with the previous listing to identify the new device (e.g., /dev/sdd)

2. Create a mount point:

sudo mkdir /mnt/data

3. Initialize the disk using fdisk:

sudo fdisk /dev/sdX  # Replace X with your disk letter

Enter these commands in sequence:

• n (new partition)
• p (primary partition)
• 1 (partition number)
• Enter (default first sector)
• Enter (default last sector)
• w (write changes)

4. Format the partition:

sudo mkfs.ext4 /dev/sdX1  # Replace X with your disk letter

Configuring Persistent Mounting

1. Get the partition UUID:

sudo blkid

2. Mount the partition:

sudo mount UUID="YOUR-UUID" /mnt/data

3. Add to /etc/fstab:

echo 'UUID="YOUR-UUID" /mnt/data ext4 defaults 0 0' | sudo tee -a /etc/fstab

4. Configure WSL automount by adding to /etc/wsl.conf:

sudo tee -a /etc/wsl.conf << EOF
[automount]
enabled=true
mountFsTab=true
EOF

Automatic Mounting on Windows Startup and WSL Shutdown/Restart

1. Create a startup script (mount-wsl-vhdx.bat):

wsl --mount --vhd "Z:\Disks\wsl-ubuntu-2404\data_disk.vhdx" --bare

2. Create a scheduled task:

• Open Task Scheduler
• Create a new task with these triggers:
  • At system startup
  • On event: Log: Microsoft-Windows-Hyper-V-Worker/Admin
    • Source: Hyper-V-Worker
    • Event ID: 18500

This ensures the disk is mounted when:

• Windows starts
• WSL restarts after shutdown
• Any Hyper-V VM starts