phatqFile locking in VMware is a safeguard to maintain the integrity of virtual machines and their associated files, especially in environments using shared storage. However, the error “Failed to lock the file” can interrupt operations, often appearing when a file like a virtual disk (VMDK) is already being accessed or locked by another process or host.
This error frequently occurs in scenarios like attempting to power on a VM already active on another host, during a vMotion process where the lock isn’t properly released, or when backup operations or snapshots interfere with file accessibility. Each instance reflects VMware’s mechanisms at work, ensuring data safety but also requiring intervention when issues arise.
Common causes include active host locking, where a VM is running on another host or the host hasn’t released the file lock due to an unexpected issue like a power outage. Orphaned lock files, often identifiable by .lck extensions, may remain in the datastore after crashes or unexpected shutdowns. Misconfigurations, such as overlapping administrative actions or improper storage permissions, can also trigger the error. Backup or snapshot processes, especially those that fail to complete cleanly, are another frequent culprit.
To identify the source of the lock, you can examine the VMware logs located in /var/log/vmkernel.log or within the specific VM’s directory. Entries referencing “Failed to lock the file” can reveal the locking host or process. Checking the datastore for .lck files associated with the VM is another way to diagnose the issue. Additionally, using the following ESXi CLI commands can help identify the lock holder:
vmkfstools -D /vmfs/volumes/datastore_name/vm_name/vm_name.vmdk
Resolving the issue often starts with ensuring the VM isn’t actively running elsewhere. Verify its status across hosts in your vSphere environment and shut it down properly if needed. Orphaned .lck files can be deleted after powering off the VM, either through a datastore browser or with a command like:
rm /vmfs/volumes/datastore_name/vm_name/*.lck.
If the lock persists, restarting VMware management services on the host can often help, using commands like:
/etc/init.d/hostd restart and /etc/init.d/vpxa restart
For more stubborn locks, the vmfsfilelockinfo utility can provide insights and allow you to release stale locks manually.
Understanding why locks occur and following these steps ensures minimal disruption while maintaining the data safety.