I've got an Ubuntu 64bit VM that I derived from a ~1GB ova file, I used it under VMware vSphere to install some more software on it and use the system against a few datasets that took some 2-3GB of space, but now that I deleted these big files, I was expecting that the newly generated ova file from it would also take about ~1.1GB of space, but instead is taking about 3GB. If I look at the details the .vmdk file in virtualbox, I see the following:

Hart Disk: SATA Port 0
Type (Format): Normal (VMDK)
Virtual Size: 8.00 GB
Actual Size:  7.90 GB
Details: Dynamically allocated storage
Location: /somewhere/myVM-disk1.vmdk
Attached To: myVM.virtualbox

The size of the ova when I export this machine is ~3GB.

Any ideas how I can shrink it?