VDI VM hard disk size cannot be modified due to an underlying snapshot dependency.

Products

• VMware vSphere ESXi

Issue/Introduction

• The hard disk was found to be associated with an existing snapshot
• The snapshot was not visible in the Snapshot Manager via the vSphere Client.
• Deleting an old snapshot of Instant Clone golden image deletes the snapshot from the vCenter Snapshot Manager however the snapshot vmdk files remain on the datastore.
• The virtual machine is identified as a Horizon VDI Golden Image, where snapshot and disk operations are managed by Omnissa Horizon

Environment

VMware vSphere 8.x

Cause

• This issue is caused if the golden image snapshot is still in use by a pool when the snapshot is deleted. This is most commonly seen when the same golden image and snapshot is in use by multiple pools but can be seen in scenarios where a golden image and snapshot is in use with a single pool but the snapshot is deleted prior to performing a new publish. 

Resolution

• Engage Omnissa Support for guidance on managing or removing the snapshot and performing disk modifications.
• Please  refer Horizon best practices, as outlined in Omnissa KB 79869.