Snapshot consolidation continues to run for a very long time.

Products

• VMware vSphere ESXi
• VMware vSphere ESX 6.x
• VMware vSphere ESX 7.x
• VMware vSphere ESX 8.x

Issue/Introduction

When attempting to consolidate snapshots via the vSphere GUI or ESXi CLI, snapshot consolidation continues to run for a very long time.

Environment

VMware ESXi

Cause

The snapshot consolidation can take a very long time to complete due to a number of factors such as the speed of the backend storage and the length of time a snapshot has been running for.

Resolution

• Allow snapshot consolidations to run until you receive an error message or it completes successfully.
• You can monitor the snapshot consolidation progress by browsing to the location of the VMDK files at the ESXi CLI and monitoring the timestamps of the VMDK files.

    cd /vmfs/volumes/Volume_Name/VM_NAME
    ls -la

• Record the timestamp and size of the flat VMDK file and wait several minutes.  You may want to take a screenshot of the CLI after running the ls -la command for reference.
• Perform another ls -la command and compare the attributes (timestamp and size) of the files inside of the VM directory to see if they have changed.  If the VMDK files are growing in size and/or the timestamp is updated to the current time (within a few minutes), the snapshot consolidation process is still working in the background and needs additional time to continue.
• Avoid starting new snapshot consolidation processes on the same datastore and/or ESXi host, if possible.
• You can attempt to stop the snapshot consolidation via the GUI, but you should not attempt to restart services to force the snapshot consolidation to stop.  Restarting ESXi services to force the VM to stop the consolidation process may result in data corruption and should be avoided if possible.
• In certain circumstances shutting a VM down and then performing a consolidation may help the process to complete, but once started the VM will not be able to power back online until the process completes or errors out.

Additional Information

See the following KBs for additional information on snapshot consolidation best practices and consolidating snapshots successfully.

Best practices for using VMware snapshots in the vSphere environment
Consolidating/Committing snapshots in VMware ESXi