How to compact virtualbox disks to save space on the host machine?

README.txt

This gist is about a tested procedure to free-up disk space on a virtualbox host machine.

I've struggled with the situation that 230GB of my 240GB SSD drive was full.
After doing these commands and follow the procedure, I could free-up more than 100GB of disk space.

The procedure copied from this answer on the superuser.com website.

https://superuser.com/questions/529149/how-to-compact-virtualboxs-vdi-file-size

Guest-Commands.md

These commands should execute on your "GUEST" OS/Your virtual machine.

If the OS is a linux, run

dd if=/dev/zero of=/var/tmp/bigemptyfile bs=4096k ; rm /var/tmp/bigemptyfile

if the OS is windows

1. Download this application http://technet.microsoft.com/en-us/sysinternals/bb897443
2. Run the command below.

Change C: with your own drive letter.

sdelete.exe c: -z

Host-Commands.md

if your host is linux run

vboxmanage modifymedium --compact /path/to/thedisk.vdi

If your host is windows run

VBoxManage.exe modifymedium --compact c:\path\to\thedisk.vdi

If your host is MacOS run

VBoxManage modifymedium --compact /path/to/thedisk.vdi