Inaccessible VMs during VCF upgrade on 4-node vSAN cluster

Products

• VMware vSAN

Issue/Introduction

You notice Virtual machines (VMs) transition to an inaccessible state within a 4-node vSAN cluster configured with a RAID-5 FTT=1 storage policy during an automated rolling patch deployment (e.g., VCF 5.2.1 to 5.2.3).

• The issue typically occurs after a host exits Maintenance Mode (MM) and VMs migrate back.
• SDDC Manager workflow fails or hangs.
• Initial host reboots may surface a "No compatible network adapters found" console error.
• vmkernel logs show cluster membership transitions and potential network isolation: Adding a new Membership entry (...) with 1 members

Environment

VMware vSAN 8.x , 9.x

VMware VCF 5.x, 9.x

Cause

NIC Teaming Policy Mismatch: Utilizing not recommended teaming policies (not standardizing on "Route based on originating virtual port" in Active/Passive) can cause network partitioning or transient driver initialization errors during lifecycle actions.

Resolution

To prevent storage inaccessibility during cluster upgrades, implement manual validation gates between host maintenance sequences:

1. Standardize the NIC teaming policy to Route based on originating virtual port in an Active/Passive configuration for all vSAN VMkernel ports.
2. Execute comprehensive cluster health pre-checks before initiating Maintenance Mode via SDDC Manager.
3. After a host exits Maintenance Mode, manually verify that all vSAN object resynchronization tasks have reached 0 bytes remaining via the vSphere Client.
4. Confirm the vSAN cluster health is 100% and all storage objects are compliant before allowing the upgrade workflow to proceed to the next node.
5. If a "No compatible network adapters found" error occurs, perform a secondary host reboot to allow the driver to initialize correctly.

Additional Information

Review KB vSAN NIC Teaming Behavior with Active/Passive Uplinks and Partial Network Connectivity Failures for more details on recommended nic teaming policy for vSAN.

Also, reference Designing the vSAN Network