Source: http://derekmolloy.ie/resize-a-virtualbox-disk/
- Make a backup copy of vdi
- In a cmd, from
c:\Program Files\Oracle\VirtualBox
execute>VBoxmanage modifyhd MyLinux.vdi --resize 100000
- Resize Linux partition:
- download GParted: http://gparted.sourceforge.net/livecd.php ISO (ex.: gparted-live-0.32.0-1-amd64.iso)
- mount GParted ISO on virtual machine cd
- resize partition dev/sda1
- click apply