@Mr. B
Apologies for the delay responding here and any inconvenience this caused. To simplify this I recommend using Azure VM backup. For Windows VMs, the Backup service coordinates with VSS to take an app-consistent snapshot of the VM disks. By default, Azure Backup takes a full VSS backup (it truncates the logs of application such as SQL Server at the time of backup to get application level consistent backup).
If you are certain you want to create a manual process let me know which OS and Application you are working with. Once I have this I can look into which specific methods you could use to freeze the IO.
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