Compacting VirtualBox Disk Images - Linux Guests

1. Start the Linux virtual machine;
2. Clean the free space on the disk of the Linux virtual machine;

   dd if=/dev/zero of=zerofillfile bs=1M

   • if= specifies the input file;
   • /dev/zero indicates a bit-stream of zeros
   • of= specifies the output file
   • zerofillfile name of the file containing the bit-stream of zeros
   • bs= indicates the block size
   • 1M indicates that the block size will be 1 megabyte

   rm zerofillfile

3. Shutdown the Linux virtual machine;
4. Use the VirtualBox VBoxManage utility to compact the Linux guest image.

Ref: Compacting VirtualBox Disk Images - Linux Guests

Grant permission for virtualbox shared folder

The regular way of getting access to the files now, is to allow VirtualBox to automount the shared folder (which will make it show up under /media/sf_directory_name) and then to add your regular user to the vboxsf group (as root #).

usermod -aG vboxsf <youruser>

Compact virtualbox hdd size