Error: Detected that the vSAN cluster is network partitioned during on-disk format upgrade pre-check for VMware vSAN.

Products

• VMware vSAN

Issue/Introduction

• vSAN Skyline Health reports 'Disk format version' alerts.
  
  
  • Disk format version

• • All hosts have a vSAN vmknic configured
  • vSAN cluster partition
    
    
• On-disk format upgrade pre-check fails with error "Detected that the vSAN cluster is network partitioned"

• Selecting the Troubleshoot option under the error "All hosts have a vSAN vmknic configured" confirms the affected host.

Environment

• VMware vSAN 7.x
• VMware vSAN 8.x
• VMware vSAN 9.x

Cause

• This issue occurs when a host is present in the vSAN cluster but cannot communicate over the vSAN network. This is common when a new host is added to the cluster without the vSAN traffic service being tagged/enabled on any VMkernel adapter.
• In vCenter, navigate to affected Host > Configure > Networking > VMkernel adapters. Verify if any adapter displays the vSAN service tag enabled.
• Login to affected ESXi host via SSH. Running the command "esxcli vsan network list" will not display any output confirming no VMkernel adapter is tagged for vSAN traffic. 

Resolution

• If the host is not intended to be part of the vSAN cluster, remove the host from the cluster before proceeding with the upgrade.

• Follow the below steps to configure the vSAN network.

1. 1. Log in to the vSphere Client.
   2. Navigate to the newly added host > Configure > Networking > VMkernel adapters.
   3. Select the adapter used for vSAN traffic and click Edit.
   4. Ensure vSAN is checked under available services.
   5. Verify the host can vmkping other hosts in the cluster over the vSAN network.
   6. Retry the on-disk format version upgrade pre-check once the network partition issues are fixed on the vSAN cluster.

• • • Navigate to the vSAN cluster.
    • Click the Configure tab.
    • Under vSAN, select Disk Management.
    • Click Pre-check Upgrade  - The upgrade pre-check analyzes the cluster to uncover any issues that might prevent a successful upgrade. Some of the items checked are host status, disk status, network status, and object status. Upgrade issues are displayed in the Disk pre-check status text box.
    • Click Upgrade.
    • Click Yes on the Upgrade dialog box to perform the upgrade of the on-disk format.

Additional Information

Upgrading vSAN Disk Format Using vSphere Client

vSAN Health Service - Cluster Health - Disk format version