vSAN Disk Group: Ineligible disk cannot be claimed

Products

VMware vSAN

Issue/Introduction

When attempting to claim a disk for a vSAN disk group, the device status shows as "Ineligible". Attempts to use the Erase Partitions feature in the vSphere Client fail with one or more of the following:

Failed to update disk partitions for /vmfs/devices/disks/...
Error: Read-only file system during write
WARNING: Partition: in-use partition 7 modification is not supported
vdq -qH output shows: Reason: Has partitions

When attempting to create a vSAN disk group or add a disk to an existing group, the vSAN device appears as 'Ineligible for use by vSAN' in vSphere Client > vSAN Cluster > Configure > Disk Management > Host > Ineligible and Unclaimed:

Environment

VMware vSAN

Cause

For a disk to be eligible for use in vSAN, it must not have any partitions on it. If any partitions exist on the disk, especially remains from previous configurations, vSAN will mark the disk as ineligible for use.

Navigate to affected ESXi host > Configure > Storage Devices. Selected the affected LUN and click on Partition details to display the partitions.

Login to SSH session for the affected ESXi host and run the below mentioned command to confirm the exiting partitions.

vdq -qH
DiskResult[11]:
Name: ######################################
VSANUUID:
State:             Ineligible for use by VSAN
Reason:            Has partitions
StoragePoolState:  Ineligible for use by Storage Pool
StoragePoolReason: Has partitions
IsSSD?:            1
IsCapacityFlash?:  0
IsPDL ?:           0
Size(MB):          3662830
FormatType:        512e
IsVsanDirectDisk?: 0

Resolution

Certain functionalities, such as vSAN or virtual flash resource, require that your ESXi host uses clean storage devices. You can erase an HHD or flash device and remove all existing data.

Make sure that the host is in the connected state.

Verify that the devices you plan to erase are not in use or used at ESXi core storage level.

Required privilege: Host.Config.Storage