How do I migrate, dump, or restore a VirtualBox system?

Solution 1:

If you're using VirtualBox 2.2.0 or newer (you should; lots of bugs fixed and bottlenecks removed) you get this out of the box. You can import and export virtual machines in the cross-solution Open Virtualization Format. You can do this both via GUI, and from scripts using the vbox command line interface. The resulting backups are cross platform.

See the VirtualBox 2.2.0 PDF manual chapter 3.8 on page 55: Importing and exporting virtual machines.

Solution 2:

Fpr Linux: If you wan't to transfer all virtual machines you can simply copy the ~/.VirtualBox folder from one machine to another. As long as the VirtualBox Versions are the same this will simply work. (I recently mounted this folder via sshfs and even this worked).