Error creating virtual machine snapshot, "An error occurred while saving the snapshot: msg.changetracker.CREATEMIRROR."

Products

• VMware vCenter Server

Issue/Introduction

• Attempting to create a snapshot of the Virtual Machine, reports the following error on the vCenter UI :

"An error occurred while saving the snapshot: msg.changetracker.CREATEMIRROR." 

• The following related log entries are observed for the virtual machine :

/vmfs/volumes/<Datastore>/<VM_name>/vmware.log : 

yyyy-mm-ddThh:mm:ssZ Er(02) vmx - DISKLIB-LIB_CREATE   : DiskLib_NotifySnapshotPrepare: FiltLib failed to notify snapshot prepare: Operation completes asynchronously
yyyy-mm-ddThh:mm:ssZ In(05) vmx - DISKLIB-CBT   :ChangeTrackerESX_CreateMirror: Created mirror node /vmfs/devices/svm/<id>-cbtmirror.
yyyy-mm-ddThh:mm:ssZ Wa(03) vmx - DISKLIB-CBT   :ChangeTrackerESX_CreateMirror: Failed to get size of the tracking info file /vmfs/volumes/<Datastore>/<VM_name>/<VM_name>-ctk.vmdk.
yyyy-mm-ddThh:mm:ssZ Wa(03) vmx - DISKLIB-CTK   :ChangeTracker_Mirror: Failed to create mirror node.
yyyy-mm-ddThh:mm:ssZ Wa(03) vmx - DISKLIB-LIB_BLOCKTRACK   : DiskLibBlockTrackPrepareChild: Failed to mirror tracking info file /vmfs/volumes/<Datastore>/<VM_name>/<VM_name>-ctk.vmdk: Could not create mirror of change tracking file (5948).
yyyy-mm-ddThh:mm:ssZ In(05) vmx - SNAPSHOT: SnapshotPrepareTakeDoneCB: Failed to prepare block track.
yyyy-mm-ddThh:mm:ssZ In(05) vmx - DISKLIB-CBT   : ChangeTrackerESX_DestroyMirror: Destroyed mirror node <id>-cbtmirror. SrcFd: /vmfs/volumes/<Datastore>/<VM_name>/<VM_name>-ctk.vmdk, DestFd: /vmfs/volumes/<Datastore>/<VM_name>/<VM_name>-ctk-mirror.vmdk.
yyyy-mm-ddThh:mm:ssZ In(05) vmx - SnapshotVMXTakeSnapshotComplete: Snapshot 0 failed: Could not create mirror of change tracking file (5).

Environment

vCenter Server 8.x

Cause

CBT is not functioning as expected. 

Resolution

• Reset CBT and then attempt to take a snapshot. 
• Follow the Broadcom KB on how to disable CBT: Resetting Changed Block Tracking for VMware vSphere virtual machines

Additional Information

When Changed Block Tracking (CBT) is disabled while the VM is still powered on, it continues to reference its associated VM_NAME-ctk.vmdk files.