vSAN Disk Group Unhealthy or Unknown Status

Products

• VMware vSAN

Issue/Introduction

• A vSAN disk group reports an unhealthy or unknown status in the vSphere Client following a Permanent Device Loss event or the physical replacement of a cache or capacity disk. This occurs when stale metadata prevents the host from recognizing the new disk as part of the existing group. Standard identification steps may sometimes fail to show the stale entry, requiring secondary verification methods.
• Other symptoms that may be seen:
  • vCenter UI displays Cluster > Configure > vSAN > Disk Management with status 'Unhealthy'.
  • Skyline Health reports "Unknown disk health state".
  • Inability to delete a disk or create a new vSAN disk group following replacement.
  • The log vob.vsan.dom.unrecoverableerror appears in VMkernel logs.
  • Command vdq -i identifies the replacement disk by a UUID instead of a standard NAA ID.

 

Environment

• Product: Broadcom VMware vSAN (All Versions)
• Component: ESXi CLI
• Architecture: vSAN OSA

 

Cause

vSAN retains a reference to the old disk UUID in the Cluster Monitoring, Membership, and Directory Services (CMMDS). If the physical disk did not fail "cleanly," this stale entry is not cleared automatically and it blocks the host from claiming the replacement hardware.

Resolution

To resolve this issue, manually remove the stale disk reference using the ESXi CLI:

1. Place the host in Maintenance Mode with the Ensure Accessibility option.
2. Connect to the host via SSH.
3. Identify the stale disk UUID using one of the following methods:
   • Primary Method: vdq -i
   • Secondary Method (if vdq -i does not show the UUID): esxcli vsan storage list
4. Force-remove the stale disk entry using the UUID identified in the previous step: esxcli vsan storage remove -u <UUID>
5. Rescan the storage adapters: esxcli storage core adapter rescan --all
6. If the disk was replaced and the replacement disk was previously used, ensure it is completely blank by navigating to Storage > Devices > Erase Partitions in the vSphere Client.
7. Recreate the disk group via the vSphere Client.
8. Verify health status and exit Maintenance Mode.

Additional Information

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