Disk Consolidation Fails with “Unable to access file since it is locked” on NFS Datastore - VMware vSphere
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Disk Consolidation Fails with “Unable to access file since it is locked” on NFS Datastore - VMware vSphere

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Article ID: 412870

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Updated On:

Products

VMware vSphere ESX 8.x

Issue/Introduction

When attempting to consolidate snapshots for a virtual machine, the task fails with the following error:
Virtual machine disks consolidation failed - "Unable to access file /vmfs/volumes/<Datastore-UUID>/<VM-Name>/<VM-Name>_X.vmdk since it is locked"

Symptoms:

  • The affected VM is unable to perform snapshot consolidation.

  • VM Migration (vMotion) and Clone operations fail.

  • VM is hosted on an NFS datastore.

  • `vmfsfilelockinfo` or `vmkfstools -D` do not show external locks (as they do not apply to NFS).

  • The VM may have a deep snapshot chain (approaching the 255-limit)

  • The issue often occurs following third-party backup operations.

  • vmkernel logs show .lck file entries pointing to the same ESXi host.

  • From var/run/log/vmkernal.log:

    YYYY-MM-DDTHH:MM:SS NFSLock: oid for existing li(lockfile .lck-500000000 file VMNAME-flat.vmdk) matches for VMNAME-flat.vmdk
    YYYY-MM-DDTHH:MM:SS NFSLock: oid for existing li(lockfile .lck-da00000000 file VMNAME_4-flat.vmdk) matches for VMNAME_4-flat.vmdk
    YYYY-MM-DDTHH:MM:SS In(182) vmkernel: cpu92:######## opID=########)NFSLock: 2456: oid for existing li(lockfile .lck-500000000 file VMNAME-flat.vmdk) matches for VMNAME-flat.vmdk
    YYYY-MM-DDTHH:MM:SS In(182) vmkernel: cpu91:########opID=########)NFSLock: 2456: oid for existing li(lockfile .lck-da0000000 file VMNAME_4-flat.vmdk) matches for VMNAME_4-flat.vmdk
    YYYY-MM-DDTHH:MM:SS In(182) vmkernel: cpu54:######## NFSLock: 2456: oid for existing li(lockfile .lck-da00000000 file VMNAME_4-flat.vmdk) matches for VMNAME_4-flat.vmdk
    YYYY-MM-DDTHH:MM:SS In(182) vmkernel: cpu60:######## NFSLock: 2456: oid for existing li(lockfile .lck-500000000 file VMNAME-flat.vmdk) matches for VMNAME-flat.vmdk

Environment

  • ESXi 8.x

Cause

Stale NFS locks remain on the VMDK files on the ESXi host where the VM resides. This typically occurs when management agents (`hostd` or `vpxa`) enter a stale state, preventing the release of the `.lck` file handle

Resolution

1. Identify the locking host

  • SSH into the ESXi host.
  • Navigate to the VM directory and identify the `.lck` files with command:
     ls -larth *.lck*
      
  • Use `hexdump` to identify the owner hostname:
      hexdump -C .lck-####
       
      *Note: Look for the hostname string in the right-hand column of the output.*

2. Place the locking ESXi host into maintenance mode with command:

  • esxcli system maintenanceMode set --enable true

3. Restart management agents on the locking host with commands:

  • /etc/init.d/hostd restart
  • /etc/init.d/vpxa restart

4. Retry disk consolidation from the vSphere Client: Right-click VM > Snapshots > Consolidate

5. Exit maintenance mode after verification with command:

  • esxcli system maintenanceMode set --enable false

Additional Information

  • This issue commonly affects VMs hosted on NFS datastores, where locking is managed by the ESXi host rather than the vCenter Server.
  • If VM logging is disabled (logging = "FALSE" in the .vmx file), enable it to improve traceability: logging = "TRUE"
  • Regular monitoring of .lck files on NFS datastores can help identify stale locks early.
  • Ensure ESXi hosts and storage firmware are running the latest versions to avoid known NFS locking bugs.

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