Alarm "Errors occurred on the disk(s) of a vSAN host" showing in vSAN Witness Host.

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:

• You see in vCenter the error "Errors occurred on the disk(s) of a vSAN host" on the summary tab of a vSAN Witness Host.
• The disks are seen as healthy in the vSAN Disk Management.
• You may also see errors with the vSAN Witness Appliance in vCenter as below:

vSAN data alarm ‘vSAN object’

vSAN physical disk alarm ‘Operation’

• You perform backups for the vSAN Witness Appliance.

Environment

vSAN 7.0.x

vSAN 8.0.x

Cause

Backups, restores, clones and snapshots of a vSAN Witness Host are not supported.

 

Resolution

Clear the errors you are seeing using the steps below and do not back up the vSAN Witness Appliance.

 

To clear the error:

1. Restart the Witness Appliance.
2. Reset the alarm "Errors occurred on the disk(s) of a vSAN host" in vCenter to green.

If a restart of the witness doesn't help, please follow:

1. Take notes of the Fault Domains in use.
2. Un-stretch the vSAN Cluster.
3. Delete the Witness Disk Group.
4. Reset the alarm "Errors occurred on the disk(s) of a vSAN host" in vCenter to green.
5. Stretch the cluster again - while performing this task, you will create a new disk group for the witness.

 

 

Furthermore, in the future instead of having backups, clones or snapshots of a vSAN Witness Appliance, use the 'Change witness host' function in the vSphere Client to deploy a new Witness Host when there is an issue with the existing Witness Host.