Unable to increase a thin-disk beyond "Maximum Size" in HTML5 client in vCenter 6.5 and 6.7

Products

• VMware vCenter Server

Issue/Introduction

Symptoms:

• HTML5 Client in vCenter 6.5/6.7 does not allow to increase the size of a thin-provisioned disk beyond "Maximum Size"

• ESXi Host Client allows to increase the size of the same thin-disk

Environment

VMware vCenter Server 6.7.x
VMware vCenter Server 6.5.x

Cause

This is a known limitation in vCenter 6.5 and 6.7 HTML5 UI

Resolution

This issue is resolved in vCenter 7.0 GA.

Workaround:
Use ESXi Host Client to increase the size of the thin-provisioned VMDK beyond free space or a larger size

Additional Information

It is expected that thin-provisioned VMDKs configured size could be larger than available free space on datastore and even larger than the datastore size.
Customers using thin provisioning are expected to monitor available space on datastore using alarms or other means and either allocate extra space to such datastore or relocate some VMs out of that datastore or do some other storage cleanup (e.g. consolidate snapshot)