User objects consuming vSAN datastore space

Products

• VMware vSAN

Issue/Introduction

Symptom:

• In vCenter, the Cluster > Monitor > vSAN > Capacity > Usage Breakdown might report large usage for the User objects.
  
  
  
  
• vSAN datastore will show the utilization more than the space space consumed by the Virtual machines.

Environment

VMware vSAN 7.x
VMware vSAN 8.x

Cause

• vSAN Objects configured with using thick provision policy will directly contributes to the inflated "User objects" capacity usage reported in vSAN datastore.
  
  
• Thick provisioning pre-allocates the entire virtual disk space, regardless of the actual data written. This is confirmed by the 'proportionalCapacity: 100' setting in the storage policy.
  
  
• Below command can be used to identify the details of the objects configured with thick provision -
  
  $ esxcli vsan debug object list --all | egrep "Object UUID:|Size:|Used:|proportionalCapacity: 100|Policy:|Path:"

Resolution

• Apply a thin provision (proportionalCapacity: 100) storage policy for those objects to free up the space from "User objects". 
  
  Steps: Menu (hamburger option on the top left, on vCenter) > Select "Policies and Profiles" > Select VM Storage Policies > Select Create or Edit (to apply already existing policy) > Under "Advanced Policy Rules", make sure Object space reservation is set to "Thin provisioning".
  
  
  Now, right click on the VM, which is associated with the impacted object > VM Policies > Edit VM Storage Policies > Select the thin provisioned, storage policy.
  
  

Additional Information

Using vSAN Policies
Resolving Storage Capacity Issues in a vSAN Datastore