How-to Consolidate virtual machine disks


When you initiate a Delete or DeleteAll operation on snapshots, the snapshot is immediately deleted, then the backing virtual machine disk .vmdk files are consolidated on-disk. If the consolidation fails [during snapshot deletion], some Virtual Disk files may remain on disk and/or be actively used on the Datastore, consuming storage capacity. (Source: VMware).

Additional space is temporarily required to perform the operation. Consolidation can be I/O intensive, it is advisable to invoke this operation when guest is not under heavy I/O usage.


Step-by-step guide - VSS Portal


  1. Login to

  2. Look for the VM to edit and click the button.

  3. From the VM action section (bottom), click on CONSOLIDATE


  4. Confirm and a consolidation task will be submitted.

Step-by-step guide - VSS CLI

Using or a local VSS CLI install

  1. Disk consolidation is treated as a change request and can be scheduled with the --schedule/-s flag. If disk consolidation is required, run vss compute vm set <name-or-id> consolidate as shown below:

    vss-cli compute vm set --schedule "2017-09-06 00:00" {Name-or-Uuid} consolidate
  2. Check the state of the request made by running:

    vss-cli request change ls -s created_on,desc -c 1

Step-by-step guide - VSS Intervention

  1. Send an email to vss(at) requesting to consolidate disks

  2. Wait for email confirmation

University of Toronto - Since 1827