Validation of vSAN disks for ESXi Host(s) failed while creating a new vSAN cluster using SDDC manager

Products

• VMware vSAN

Issue/Introduction

Symptoms:

Getting error when creating a new vSAN cluster using SDDC manager: 

Description	Validate vSAN disks for ESXi Host(s)
Progress Messages	vSAN Disks Validation on the ESXi Host(s) failed: vSAN cache/capacity disks ratio must be more or equal to 1:7, vSAN cache/capacity disks ratio must be more or equal to 1:7, vSAN cache/capacity disks ratio must be more or equal to 1:7
Error	Message: vSAN Disks Validation on the ESXi Host(s) failed: vSAN cache/capacity disks ratio must be more or equal to 1:7, vSAN cache/capacity disks ratio must be more or equal to 1:7, vSAN cache/capacity disks ratio must be more or equal to 1:7 Remediation Message: Make sure that ESXi Hosts disks are eligible for use by vSAN Reference Token: MMDIQQ Cause:

Environment

VMware vSAN 7.x

VMware vSAN 8.x

Cause

The SDDC manager will look at the disks eligible for use by vSAN and use those disks to create disk groups.

If the OS disk of the host is marked as eligible to use by vSAN, then this issue can occur.

We will see the below snippet in the domainmanager.log logfile in the SDDC manager:

The eligibility can be verified by the below command:

vdq -qH

 

 

Resolution

Have the OS partition installed on the correct OS disk and the disk should show ineligible to use by vSAN as below:

Once the OS disk will be marked as ineligible, the SDDC manager will not probe it when trying to create a disk group.