Snapshot usage on ESA Cluster is very high

Products

• VMware vSphere ESXi

Issue/Introduction

• In vCenter UI, Cluster > Monitor > vSAN > Capacity shows the Usage by snapshot as very high.
  
  
  
  

• Snapshot Manager for the Virtual machines may not show any Snapshots consuming this much space. However, the Virtual machine folder will have multiple snapshot disks.
  
  
• Overall usage on the vSAN datastore will increase due to the snapshot space usage.

Environment

VMware vSAN 8.x
VMware vSAN 9.0

Cause

This issue happens when the Snapshot consolidation fails because the system is unable to delete the Change Block Tracking (-ctk.vmdk) file.
This failure causes the snapshot deletion task to abort, leaving the snapshot VMDKs behind and consuming massive amounts of capacity over time.

/vmfs/volumes/vsan:##/<VM_name>vmware.log shows Snapshot consolidation failures for the VMs. The failures occur during the deletion of the snapshot's change tracking (-ctk.vmdk) file.

2025-12-06T02:56:53.773Z In(05) vcpu-0 774c0453-c3-dbd9 DISKLIB-CTK   : Could not unlink tracking file "/vmfs/volumes/vsan:##/<VM_Name>/VM_Name-ctk.vmdk".
2025-12-06T02:56:53.773Z In(05) vcpu-0 774c0453-c3-dbd9 DISKLIB-LIB_BLOCKTRACK   : Warning: could not stop change tracking info: Could not delete change tracking file (10).
2025-12-06T02:56:53.773Z Er(02) vcpu-0 774c0453-c3-dbd9 DISKLIB-LIB   : DiskLibUnlinkInt: Disk delete failed to complete { result:2620, errMsg:'Could not delete change tracking file', fileName:'/vmfs/volumes/vsan:##/<VM_Name>/VM_Name.vmdk'}

The error result:2620 translates to DISKLIBERR_CHANGETRACK / CTK_CTKUNLINK.

vmware-2.log:2025-12-06T02:56:53.773Z Er(02) vcpu-0 774c0453-c3-dbd9 DISKLIB-LIB   : DiskLibUnlinkInt: Disk delete failed to complete { result:2620, errMsg:'Could not delete change tracking file', fileName:'/vmfs/volumes/vsan:##/<VM_Name>/VM_Name.vmdk'}
vmware-2.log:2025-12-07T14:39:09.416Z Er(02) vcpu-0 c4a472c-6a-5417 DISKLIB-LIB   : DiskLibUnlinkInt: Disk delete failed to complete { result:2620, errMsg:'Could not delete change tracking file', fileName:'/vmfs/volumes/vsan:##/<VM_Name>/VM_Name-000001.vmdk'}
vmware-2.log:2025-12-07T20:54:11.143Z Er(02) vcpu-0 397cd015-68-6e88 DISKLIB-LIB   : DiskLibUnlinkInt: Disk delete failed to complete { result:2620, errMsg:'Could not delete change tracking file', fileName:'/vmfs/volumes/vsan:##/<VM_Name>/VM_Name-000002.vmdk'}
vmware.log:2026-04-07T21:04:46.271Z Er(02) vcpu-0 - DISKLIB-LIB   : DiskLibUnlinkInt: Disk delete failed to complete { result:2620, errMsg:'Could not delete change tracking file', fileName:'/vmfs/volumes/vsan:##/<VM_Name>/VM_Name-000003.vmdk'}

Resolution

This issue is fixed in VCF 9.1 version.

However, to clear the existing orphaned snapshot, please reach out to Broadcom Support.