I'll have to experiment with this again. 3-4 years ago in my homelab I had a Windows VM on a thinly provisioned disk and I was able to watch it push unmaps down to storage in real time. It was an automatic process, as in delete a large file inside the VM and watch the unmaps start flowing maybe 15-30 seconds later. It only worked if Windows could detect that it was running on thinly-provisioned disk
I don't remember what storage I was using at the time; it was either iSCSI to FreeNAS or iSCSI to a Windows Server running the iSCSI target service. I also don't remember if said Windows VM was on VMware Workstation or on ESXi.
But now I'm curious and I plan to run a few experiments...
Some light reading:
Thin Provisioning and Trim Storage Overview | Microsoft Learn
Plan and Deploy Thin Provisioning | Microsoft Learn
Thin Provisioning Performance Test - NTFS (LOGO) | Microsoft Learn
Thin Provisioning SCSI Compliance Test (LOGO) | Microsoft Learn
Of interest to OP regarding thin/thick performance:
Thin Provisioning Performance Test - RAW Disk (LOGO) | Microsoft Learn
