No disk space anomaly

Hi all,
I am following a tutorial from the book “Linux Observability with BPF”. Their examples are based on a Vagrant vm. Specifically fedora-30-cloudbased.

I was able to get a Fedora-30-cloudbased system running in Virtualbox using Vagrant. The ‘cloudbased’ simply means that it is a bare-bones version of Fedora originally intended for use on cloud virtual machines.

Vagrant created a virtual disk for the vm in my ‘home’ directory. My home directory is installed on a real 1TB partition with about 600GB of storage available. The virtual disk is named “Fedora-Cloud-Base-Vagrant-30-1.2.x86_64.vmdk” According to virtual-box, The size of the virtual disk is 40GB.
Running the virtual machine, ‘df’ shows a 40GB disk drive available. ‘du’ shows disk usage of 1.6GB. However, when I try to add a new file i get the error "NO DISK SPACE AVAILABLE’. Using ‘sudo’ to create a file doesn’t help.

I am running virtualbox 6.0. My ‘host’ system is Linux mint 20.0. I have a virtual ‘Windows-XP’ and virtual ‘Linux Mint’ installed and both are working correctly. The only difference I can see is that the virtual Fedora-30 uses a ‘.vmdk’ disk and my other vms use ‘.vdi’ disk.

I guess my question is how can I change my Fedora-30 setup to use vdi instead of vmdk.

Thanks in advance for any advice.
Best regards,
Bob G.