Reduce the size of VirtualBox virtual hard disk files under Ubuntu 16.04

Windows is typically installed in VirtualBox and then used in a seamless mode for certain software.

The VirtualBox virtual hard disk will be larger, and the VirtualBox does not have its own cleanup tool, compared to VMware, VMware comes with a defrag tool.

Here are the specific cleanup methods:

1. If the virtual machine is using a system that is windows:

① into the virtual machine, download sdelete,:http://technet.microsoft.com/en-us/sysinternals/bb897443.aspx.

② running on the command line

Sdelete.exe-z C:

Remember: You cannot use the-c parameter, otherwise you will wear SSD.

This period will stay at 100% for a long time until it is complete.

③, when finished, shut down the virtual machine, compress the VDI files up and down in Ubuntu commands as follows:

Vboxmanage MODIFYHD Xxx.vdi--compact

④ if it is not the VDI format, you need to do a conversion with the following command:

Vboxmanage Clonehd source.vmdk CLONED.VDI-format  vdivboxmanage MODIFYHD cloned. VDI--compactvboxmanage Clonehd cloned. VDI COMPRESSED.VMDK--format VMDK

2. If you are using a Linux virtual machine:

Step ③④ above, the previous steps should be changed to:

if=/dev/zero of=/empty bs=/empty

There is also an option to use the Zerofree command as follows:

BusyBox mount-o ro,remount/dev/sda1  /dev/sda1  busybox mount-o rw, REMOUNT/DEV/SDA1  

Reference:

Https://superuser.com/questions/388733/virtualbox-how-to-free-up-unused-vdi-disk-place

http://blog.csdn.net/god2469/article/details/8525880

http://blog.csdn.net/ganshuyu/article/details/46360271

http://blog.csdn.net/cnylsy/article/details/52474513

https://forums.virtualbox.org/viewtopic.php?p=29272#p29272

Reduce the size of VirtualBox virtual hard disk files under Ubuntu 16.04