"Failed to place witnesses" error when taking snapshot on VM on vSAN stretched cluster

Products

• VMware vSAN

Issue/Introduction

When taking a snapshot of a VM, an error message like the below is seen.

 

"Failed to place witnesses. There are currently 0 usuable disks and 1 more usable disks are needed in witness node. An error occurred while taking a snapshot: 22 (Invalid argument)."

Environment

vSAN OSA

Cause

The disk(s) on the vSAN witness appliance are unhealthy.

 

To confirm this, click on the vSAN Cluster, then go to: Configure --> vSAN --> Disk Management

 

If the disks on the vSAN witness appliance cannot be written to, witness component creation will fail, which will prevent the creation of vSAN objects.

Resolution

Reboot the witness appliance.

- This operation is safe to complete as, if the disks on the appliance are showing as unhealthy, vSAN management will not be able to communicate with them anyway.

 

If the disks on the vSAN witness appliance are still unhealthy after reboot, then recreate the vSAN disk group on the witness appliance.

- Warning: Ensure this operation is done only on the witness appliance, and not on any of the data nodes, as with witness component data unavailable, the vSAN object data will be in a reduced availability state.

 

If this still does not resolve the problem, then deploy a new witness appliance.