Snapshot or Backup Fails with Error: msg.changetracker.MIRRORCOPYSTATUS

Products

• VMware vCenter Server
• VMware vSphere ESXi

Issue/Introduction

• Attempts to take a manual snapshot, clone a virtual machine (VM), or run third-party backups fail. The vSphere Client UI displays the following error:

        An error occurred while saving the snapshot: msg.changetracker.MIRRORCOPYSTATUS. An error occurred while taking a snapshot: msg.changetracker.MIRRORCOPYSTATUS


   

• From ESXi hostd logs (/var/log/hostd.log) shows failure during the transition to the snapshot state:
  
  YYYY-MM-DDTHH:MM:SS In(166) Hostd[####]: [Originator@6876 sub=Vmsvc.vm:/vmfs/volumes/vsan:5284a75########-#####/#######-5eb0-###-1c4e-#####/###.###-####.###.vmx opID=###-c5-4f9d sid=52b8626f user=vpxuser:VSPHERE.LOCAL\###] State Transition (VM_STATE_ON -> VM_STATE_CREATE_SNAPSHOT)
YYYY-MM-DDTHH:MM:SS Db(167) Hostd[####]: [Originator@6876 sub=Vigor.Vmsvc.vm:/vmfs/volumes/vsan:#####-545b21db########/#####-5eb0-99df-1c4e-######/####.tr-###.####.vmx] Create Snapshot message: An error occurred while saving the snapshot: Could not get mirror copy status.
YYYY-MM-DDTHH:MM:SS Db(167) Hostd[####]: --> An error occurred while taking a snapshot: Could not get mirror copy status.
  
  
  
• From Virtual Machine logs (/vmfs/volumes/datastore/vm-name/vmware.log)shows  the process failed because a disk lock was lost:
  
  YYYY-MM-DDTHH:MM:SS Wa(03) vmx - DISKLIB-CBT   : ChangeTrackerESX_GetMirrorCopyProgress: Failed to copy mirror: Lost previously held disk lock
YYYY-MM-DDTHH:MM:SS In(05) vmx - DISKLIB-LIB_BLOCKTRACK   : DiskLibBlockTrackMirrorProgress: Failed to get mirror status of block track info file /vmfs/volumes/vsan:######-545b21d#######/#####-99df-1c4e-#####/###.tr-####.r###_1-###.vmdk.
YYYY-MM-DDTHH:MM:SS In(05) vmx - DISKLIB-CBT   : ChangeTrackerESX_DestroyMirror: Destroyed mirror node 5###-26#####c-cbtmirror. SrcFd: /vmfs/volumes/vsan:######-545b21#######/#####-5eb0-99df-1c4e-######/te@####n.tr-####.####_1-#####.vmdk, DestFd: /vmfs/volumes/vsan:#####-######7b57/######-####-#####/####.tr#####
YYYY-MM-DDTHH:MM:SS In(05) vmx - SNAPSHOT: SnapshotPrepareTakeDoneCB: Failed to prepare block track.
YYYY-MM-DDTHH:MM:SS Wa(03) vmx - DISKLIB-CBT   : ChangeTrackerESX_GetMirrorCopyProgress: Failed to copy mirror: Lost previously held disk lock

Cause

This issue is caused by a file lock conflict related to the Changed Block Tracking (CBT) mirror status. Primary triggers include:

• Stale CBT State: Stale data remaining after a VM restoration.
• Backup Timing Conflicts: Race conditions between backup tool requests and ESXi snapshot/consolidation processes.

 

Resolution

To clear the stale lock and refresh the mirror status:

1. Migrate the VM: Use vMotion to move the virtual machine to another ESXi host.
2. Verify: After migration, attempt to create and delete a manual snapshot to confirm the issue is resolved.