I created an Ubuntu VM and set the Primary vDisk size to 550G.  After installing the OS, it looks as if I only have 196G allocated to the drive.   On the VM screen in the UI it lists capacity at 550G and Allocation at 152G.  I assume resizing with Ubuntu will be painful and don't mind rebuilding the machine but I can't seem to see an obvious setting to ensure this doesn't happen again.

How much free space is showing in the VM? vdisks are sparse by default, so they only show allocated what is actually in use by the VM.

This turned about to be an Ubuntu issue.  Despite telling Ubuntu to use all of my disk space it only created a 196G partition.  I was able to use lvextend and resize2fs to extend the logical volume.  I have yet to understand this functionality but by creating additional VMs I was able to replicate it.