CBT-enabled First Class Disk (FCD) can be attached to a CBT-disabled Virtual Machine from vSphere 9.0 and later

Products

• Tanzu Kubernetes Runtime

Issue/Introduction

This article explains the enhancement that allows a Change Block Tracking (CBT) enabled First Class Disk (FCD) to be attached to a CBT-disabled virtual machine (VM) with vSphere 9.0 and later versions.
In earlier vSphere versions, this operation was not supported. Attaching a CBT-enabled FCD to a VM with CBT disabled fails. Workaround previously required keeping VMs CBT-enabled before attaching the FCD or disable the CBT on FCD. "The operation is not allowed in the current state" error when trying to attach a Persistent Volume to a Kubernetes worker node

Environment

vSphere with Tanzu

Cloud Native Storage

vSphere 9.x

Resolution

This issue is resolved in ESXi 9.0 and later.

The CBT state of the FCD and the CBT state of the VM are now managed independently, removing the previous dependency.
With this enhancement, an FCD can be attached successfully to a VM regardless of CBT state. FCD CBT state does not automatically inherit or overwrite the VM CBT state.

Additional Information

Behavior prior to 9.x 

Behavior from 9.x and later

The attachment will always succeed whatever the CBT states of the FCD and the VM are in.