Unable to take snapshots on a VM in a vSAN Cluster

Products

• VMware vSAN
• VMware vCenter Server

Issue/Introduction

When you look at the "Summary" of the VM in vCenter you will see that the storage policy shows "Non-compliant" despite being the correct vSAN storage policy. In this case, the vSAN should show as healthy and you will still be able to power on the VM. 

 You may also encounter any of the following symptoms: 

• The VM shows "0mb" used space even when powered on 
• Unable to take snapshots on a VM 
• Unable to resync the vSAN cluster

Environment

• VMware vSAN 8.0.x
• VMware vSAN 7.0.x
• VMware vCenter Server 8.0.x
• VMware vCenter Server 7.0.x

Cause

This is caused when vCenter is out of sync with the VM storage policy. The mismatching storage policy will cause vCenter to report that the VM is out of compliance. As a result, vCenter will fail any snapshot or resync on the non-compliant VM. 

Resolution

In order to resolve this issue: 

1. Navigate to the VM in the vCenter Inventory 
2. Consolidate any snapshots on the VM 
3. Right click the VM 
   1. Select "Edit Settings"
   2. Change the vm storage policy to a different policy. 
   3. Complete the wizard and apply the change.  
   4. Allow time for the VM to resync (this can take a while) 
4. Right click the VM again 
   1. Select "Edit Settings"
   2. Change the vm storage policy back to the correct policy. 
   3. Complete the wizard and apply the change. 
   4. Allow time for the VM to resync (this can take a while) 

This will force vCenter to resync the storage policy and put them in sync again. 

Additional Information

For more information see vSAN Storage Policy Compliance and Resync the vSAN cluster