Windows 10 VMs using thin pool, both linked clones of same template. One with lower disk usage has much higher backup size

I'm backing up two Windows 10 VMs, both from the same linked Windows VM clone, and both quite recent.

Both are linked clones of the same template, and have only been setup for a few days.

I'm taking both backups using the same ZSTD / snapshot settings, and both while the VMs are shut down (so memory not being captured)

Looking at the disk usage vs backup size I see:

VM 1 36.5GB used - backup file is 19GB
VM 2 28.8GB used - backup file is 37GB

All I can think is the VM2 somehow had a...

Read more