Snapshot creation fails: "Object policy is not compatible with datastore space efficiency policy configured on the cluster"

Products

• VMware Cloud on AWS
• VMware vSAN

Issue/Introduction

• Snapshot creation fails during virtual machine backup:
  Object policy is not compatible with datastore space efficiency policy configured on the cluster. An error occurred while taking a snapshot: 22 (Invalid argument).
• Virtual Machine power on fails:
  Module VMMon power on failed. Failed to start the virtual machine. Failed to power on VM. Could not power on virtual machine: Failure. Failed to create swap file.
• Virtual Machine vMotion fails:
  A general system error occurred: Launch failure 2025-10-14T03:22:19.970158Z The VM failed to resume on the destination during early power on. Module VMMon power on failed. Cause: Module VMMon power on failed. 2025-10-14T03:22:19.970158Z The VM failed to resume on the destination during early power on.
  
  
• Error seen in the clomd.log file on the host:
  CLOM_CheckClusterResourcesForPolicy: Target datastore space efficiency policy is not compatible with current cluster configuration. DedupAndCompression:1, CompressionOnly:0, None:1

Environment

VMware vSAN 8.x 

VMware Cloud on AWS

Cause

• This is a known issue caused by the vSAN Witness Host disks being marked as having "Deduplication and Compression" enabled but not being marked as the vSAN Witness Host. 
• Due to the vSAN Storage Policy having "Space efficiency" set to "Deduplication and Compression", the incompatibility error is seen and the vswp file creation fails. 

Resolution

• There is currently no resolution for this issue. 
• The current workaround is to restart the vSAN CLOMD service on all hosts in the cluster. 
• If this is a VMC on AWS environment, open a support ticket with the VMC on AWS Global Support team to have the service restarted on the hosts. 

Additional Information

• Virtual machine creation or power on fails on vSAN Cluster with Error - Invalid virtual machine configuration. Object policy is not compatible with datastore space efficiency policy configured on the cluster (This article is relevant for on-premise VCF environments and not VMC on AWS environments)
• vSAN Health Service - Cluster Health – vSAN daemon liveness check