Shrinking VMware Virtual Disks

The guest cannot have snapshots and it cannot be marked as a template from which clones are made.

In VMware Workstation:

• For Windows guests:
  • Start the guest system and log in
  • Open a command prompt window in administrator mode
  • C:\Program Files\VMware\VMware Tools\VMwareToolboxCmd.exe disk list
  • C:\Program Files\VMware\VMware Tools\VMwareToolboxCmd.exe disk shrink C:\
• For Linux guests:
  • Start the guest system and login as root
  • Open a terminal window
  • vmware-toolbox-cmd disk list
  • vmware-toolbox-cmd disk shrink /

In ESXi:

• For Linux guests using LVM volumes:
  The zerofree utility is much quicker than the old "dd if=/dev/zero" method and it does not expand the thin-provisioned volume to full size, but it requires that the partition be unmounted.
  • Download the systemrescuecd.iso and place it on one of the ESXi server's datastore volumes
  • Remove any snapshots
  • Modify the guest system's settings so that it boots from the ISO image
    • Change "Boot Options" to "Force BIOS Setup"
    • Set the CD drive to "Connected" and and point it at the ISO image
    • Restart the guest and, in boot settings, set it to boot from the CD ahead of the hard drive
    • "Save and Exit" to boot the guest into the systemrescuecd image
  • Activate the LVM volume that contains the root partition
    • Activate all volume groups

      lvm vgchange -a y

    • List all volumes and their volume groups

      lvm lvs --all

  • Zero out the root volume

    zerofree -v /dev/volume_group/volume

    in my case that's

    zerofree -v /dev/vg_ioc51prod/lv_root

  • Shutdown the systemrescuecd guest system
  • Modify the guest system's settings to restore the original boot settings
    • Remove the systemrescuecd.iso as the CD device
    • Change "Boot Options" to "Force BIOS Setup"
    • Power on the guest and set it to boot from the hard drive ahead of the CD in boot settings
    • "Save and Exit" to boot the guest to confirm that it still works
  • Shutdown the guest
  • SSH to the ESXi server
  • Locate and change to directory that contains the guest's VMDK file
  • vmkfstools --punchzero <guest>.vmdk