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vdi management

September 26, 2020


vdi files are VirtualBox native virtual drive containers. These can have a fixed size or be dynamic, consuming as much space as is needed.

  • "Hardware virtualization" deals with how to convert a real partition into a vdi container for use within VirtualBox
  • "Compact vdis": At some point you might want to shrink such dynamic disk containers to ease maintenance (backup for example)

Hardware virtualization

Tested with Windows 7

  1. disk2vhd: create a vhd (without vhdx!)
  2. transform the vhd into vdi with VBoxManage clonehd
  3. setup a vm with VirtualBox & test if you can boot the vdi
  4. Check the drivers, eventually remove the PCI bus driver if you get Code 12 errors. In my special case I had trouble with AMD pci express 3gio filter
  5. Re-activation of the windows key in the VM (do not use old system anymore!!)

Compact vdis

To shrink dynamic drives to a reasonable size (almost same as actually used bytes) follow the procedure here:

See https://www.howtogeek.com/312883/how-to-shrink-a-virtualbox-virtual-machine-and-free-up-disk-space/

Windows guest

  • use defragmenter to defragment / compact the filesystem
  • use sdelete to zero out unused space sdelete.exe c: -z

Linux guest

  • use zerofree


  • Run VBoxManage modifymedium disk <vdi file> --compact