Hyper-V 2016 Cluster - Checkpoint not cleared

Question

Running Windows Server 2016 setup as a Hyper-V cluster with two servers clustered with about 10 guests running on the cluster. One guest server running Windows 2016 does not remove / merge checkpoints when deleted. The server did not have issues until about a week ago. When a checkpoint is created either mnaually via the Hyper-V Manager or Cohesity backup process the checkpoint is not merged in when deleted or the job is done. Doing an edit disk and merge removes the checkpoints but the next time the process runs the checkpoints are not removed. Looking at the folder structure for the VM there is an VMCX file in the snapshot folder from the date the issue started. Storage is shared storage on running on Pure Storage.

How do we correct the issues with checkpoints not being cleared correctly when deleted?

Answer 1

Hi,

Thank you for your posting!

Based on your descriptions, I would like to check:

what do you mean "the process runs the checkpoints are not removed" ? After you delete your checkpoints, they are merged into your vhd(x) file, so when the process runs the vhd(x) file, it also runs the removed avhd(x) files (the checkpoints). So I guess you mean, even though you delete the checkpoints, they still take up your storage space?

Secondly, sometimes after we delete the checkpoints, they still exist on Hyper-V Manager, but actually they are truely removed. So, I would like you to check whether you have already deleted your checkpoints. You can follow the next two options:

1) Run Remove-VMSnapshot command from PowerShell:

https://learn.microsoft.com/en-us/powershell/module/hyper-v/remove-vmsnapshot?view=windowsserver2019-ps

2) Make sure that the checkpoint locations are set on shared storage. Go to the location where you set your checkpoints, check if there are any removed avhd files left.

Thank you for your understanding and support!

BR,
Joan

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Answer 2

After a backup process is run by Cohesity the checkpoint is removed from the GUI for the server in Hyper-V Manager and the setup in Failover Cluster Manger still shows the disk for the server as the differencing disk, the files do not appear to be merged when the backup process completes. In the shared storage folder the snapshot files still exist and are not removed.

Running
Get-VMSnapshot for the server shows no snapshot and running remove-vmsnapshot does not remove the files.
The VM and checkpoint files reside on shared storage. Several other servers on the same volume have no issues with checkpoints. Once a checkpoint is deleted the files are removed.

Answer 3

Hi,

Thanks for your patience!

Based on your descriptions, I would like to firstly check a few things for you:

1) "the files do not appear to be merged when the backup process completes" ——

Since you have already removed your checkpoints from the GUI for the server in Hyper-V Manager, how did you know the files were not merged into vhd files? When you delete your avhd files successfully, they should automatically be merged into their original files.

2) "In the shared storage folder the snapshot files still exist and are not removed." ——

Can you give me some screenshots for this issue? I can only suppose that you may backup your avhd files in your shared storage, they do not necessarily need removing since they should not influence your original avhd files and their vhd files.

3) Try to check the locations that I showed you last time, to see if any avhd files remain with their vhd files.

Thanks for your understanding and support!

BR,
Joan

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