Disk file ext4.vhdx takes too much space

[FoliageOwO]

Hi. I'm new to playing with a WSL. I've used the ArchWSL for a while, but I found my disk almost full when installing stuff.

After running gdu -i /mnt in the ArchWSL, it told me the WSL only used 18.4 GiB:

But the disk file occupies 50+ GiB:

Environment:

• Windows build number: 10.0.22631.3737
• Security Software: Windows Defender
• WSL version 1/2: WSL 2.2.4.0
• ArchWSL version: 24.4.28.0
• ArchWSL Installer type: zip
• Launcher version: 24042000

Additional context
Seemed to have a connection with this issue WSL#8226, for which I did Optimize-Vhd /path/to/the/ext4.vhdx on my PowerShell, and it threw me an error:

Optimize-VHD: Failed to compact the virtual disk.

Failed to open attachment '/path/to/the/ext4.vhdx'. Error: 'The requested operation could not be completed due to a virtual disk system limitation.  Virtual hard disk files must be uncompressed and unencrypted and must not be sparse.'.

I followed the instructions of the reply on the issue WSL#4103, which did nothing.

Is the space the disk file takes normal, or my settings for ArchWSL is wrong?

[lucasacoutinho]

Hi @FoliageOwO, I’m not sure if you still need help, but I recently faced the same issue, so I thought I'd share my solution for anyone else encountering it.

My distro was set to sparse for a while, which caused some complications. I resolved it by running:

wsl --manage <distro> --set-sparse false

After doing this, I was able to use optimize-vhd without any issues. Once you're done, you can re-enable sparse mode if you like, but I recommend running this process periodically—especially if you notice an unusually large disk usage.

For reference, I’m using the default Ubuntu distro, but this solution should also work for ArchWSL and others.

[FoliageOwO]

@lucasacoutinho Thanks, this really does work! :)