Disk/Partition size increases 'strangely' over time

[MarcoCouto]

Operating System: Ubuntu 16.04 xenial
Vagrant Version: 2.2.7
Virtual Box Version: 6.1.4

Hi!

I've been using this Vagrant box for the past month or so.
Recently, my host machine kept telling me that it was running out of disk space. I struggled to understand why, but eventually looked at the Virtual Box VMs folder, and discovered that the vccw one was using almost 40 GB.

I thought this was quite unusual, considering that my other Vagrant VMs were using no more than 7GB. I opened Virtual Box, and under the VM's settings -> Storage, I clicked on the disk and the Virtual Size was set to 64GB, and the Actual Size was almost 40GB.

I entered the VM's shell, and ran the command df -h to understand what was going on, and I have two partitions, named vagrant and var_www_html, of 145GB (from which 93GB are used), and the /dev/vagrant--vg-root partition was nowhere near the 40GB of used space.

I ran the command du -h -a -d 1 /, and I only have a few GB of used space. So, either Vagrant or Virtual Box somehow "extended" the Actual Size of vccw's disk to 40GB, even though it is not using it.

Is there any idea why this is happening? Is it fixable?
I tried halting, then destroying the vccw machine, and finally removing the vccw box from my host, and repeated the up + provision step. After a few days of developing, I noticed the Actual Size is again increasing, and once again the amount of GB used does not correspond to it.

[LouisJackson]

@MarcoCouto I'm curious, did you find a solution for this?