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

[marcosscriven]

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 large file on its C: drive that's been removed, but that from the point of view of the thin-pool LVM volume that's not been released.

If this is correct, how do I verify and correct this please?

 

[oguz]

hi,

is the discard option set for the drives for those VM?

you can also install sdelete from sysinternals and zero the free space with sdelete -z

 

[marcosscriven]

@oguz - thanks, I just got around to trying that, and it reduced my backup size from 40G to 10G.

 

[oguz]

great! please mark the thread as [SOLVED] by editing the thread title prefix