====== Zero-Fill Disk Drive Free Space ======

There may be various reasons to zero-fill the free space on a disk drive:

  * Make the disk **more compressible** for backup
  * **Faster** than a secure-erase
  * Will force a drive to **retire any bad sectors** in empty space before they are reused

<note warning>Do **not** do this on SSD drives!</note>

<note warning>This may cause a thinly provisioned virtual disk to balloon out to it's fully provisioned size!  But it can also have a profound impact in the size of VM (image) backups.</note>

===== Windows =====

https://docs.microsoft.com/en-us/sysinternals/downloads/sdelete

<file>
sdelete -z x:
</file>

:!: ''sdelete'' can also be used for secure erase.

===== Linux =====

https://community.linuxmint.com/software/view/zerofree

https://snippets.khromov.se/shrinking-a-virtualbox-linux-image-with-zerofree/

<file>
zerofree /dev/sdx1
</file>