Consolidating snapshot fails or ineffectively after third party backup succeeds or fails

Products

• VMware vSphere ESXi

Issue/Introduction

For KB Consolidating snapshot fails after third party backup succeeds (57325) provides solution.

Symptoms:

• VM cannot migrate storage.
• Snapshot files are not visible in vSphere Client.
• There are VM_name-00000#-sesparse.vmdk/VM_name-00000#-delta.vmdk and 00000#-ctk.vmdk files in the VM data directory.
• Conforms to the description in KB Consolidating snapshot fails after third party backup succeeds (57325) Symptoms

 

Environment

VMware vSphere ESXi 7.0.x

VMware vSphere ESXi 8.0.x

Cause

See KB Consolidating snapshot fails after third party backup succeeds (57325) for details

Resolution

There are 3 solutions.

（1）Solution 1: Clone VM (recommended)

Use a clone instead of an existing VM. Cloned VM not only backs up the data in the original VM, but also forces snapshot consolidation on original VM. After cloning the VM, turn on the cloned VM with the NIC disconnected and see if the services inside can run properly.

（2）Solution 2: Restore VM

Restore VM using backup software. then save and import the current data into the restored VM for data consistency.

（3）Solution 3:  Manual Consolidation Snapshot

If the clone fails in the snapshot session, the disk can only be cloned manually

Manually clone the vmdk disk of the VM using vmkfstools. ( VMs need to be shut down)

1. Use the command 

   vmkfstools -i <source file vmdk>.vmdk <DESTINATION VMDK FILE>.vmdk -d thin -a buslogic

   to manually clone the vmdk disk for the VM . for detail please see Cloning a Virtual Disk from Snapshots
2. After cloning the disk, if the ctk file still exists, you can first go to the vmdk descriptor file and comment out the ctk option.
3. Create a new virtual machine with the same configuration as the original virtual machine.

（4）Solution 4: waiting for backup software to perform the task again.

In some situations, third-party backup software consolidates snapshots automatically when performing backup tasks again. We need to observe the VM folder to confirm.

If the above 4 solutions cannot be solved, you have to rebuild a new vCenter Server Appliance.

Additional Information

Impact/Risks:

Snapshots are not consolidated after a backup completes. Virtual machines cannot migrate storage.