Unable to create any objects on a healthy vSAN datastore.

Products

• VMware vSAN 8.x

Issue/Introduction

When attempting to create any objects on the vSAN datastore it fails with the error, "Cannot complete file creation operation. Object policy is not compatible with datastore space efficiency policy configured on the cluster."

• When viewing the vSAN health under vSAN > Skyline Health there are no major issues. If there are any major issues showing in vSAN health those should be addressed first.
• The vSAN storage policy shows that deduplication and compression are in use.
• The vSAN disks groups indicate that deduplication and compression are enabled when viewed using the command: esxcli vsan storage list (see example output below)

naa.XXXXXXXXXXXXXX
   Device: naa.XXXXXXXXXXXXXX
   Display Name: naa.XXXXXXXXXXXXXX
   Is SSD: true
   VSAN UUID: XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
   VSAN Disk Group UUID: XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
   VSAN Disk Group Name: naa.XXXXXXXXXXXXXX
   Used by this host: true
   In CMMDS: true
   On-disk format version: 20
   Deduplication: true
   Compression: true
   Checksum: 12345678901234567890
   Checksum OK: true
   Is Capacity Tier: false
   Encryption Metadata Checksum OK: true
   Encryption: false
   DiskKeyLoaded: false
   Is Mounted: true

• This will most likely not impact any running virtual machines since those objects are already created. 

Environment

• VMware vSAN 7.x
• VMware vSAN 8.x
• VMware vSAN OSA

Cause

This is caused by a discrepancy in the vSAN configuration between how the vSAN disk groups are configured which show TRUE for both deduplication and compression, and vCenter which shows None for the Space efficiency setting.

• If you navigate to the vSAN cluster. Click the Configure tab, then under vSAN, select Services. In the Data Services section for Space efficiency it shows None:

Resolution

In order to resolve this issue the vSAN configuration must be consistent for all settings. Otherwise, it will fail to create any objects, and could lead to other unexpected behavior. The most efficient way to resolve this is to Enable Deduplication and Compression on an Existing vSAN Cluster by following these steps.

1. Navigate to the vSAN cluster.
2. Click the Configure tab.
3. Under vSAN, select Services
   1. Click to edit Space Efficiency.
   2. Select a space efficiency option: Deduplication and compression, or Compression only. (NOTE: This setting must match the setting that is currently enabled on all vSAN disk groups noted above when running the command esxcli vsan cluster get) 

Note:

While enabling deduplication and compression on a vSAN OSA cluster, vSAN updates the on-disk format of each disk group of the cluster. To accomplish this change, vSAN evacuates data from the disk group, removes the disk group, and recreates it with a new format that supports deduplication and compression. This will likely happen even if deduplication and compression are already enabled on the disk groups.