On my two Windows 10 VMs, when I delete data on a disk, it's size in Unraid doesn't go down. For example, I have a 64G on my main VM with about 50G of used space. If I copy a 1GB file to it, the disk size in Unraid shows it's 51G. If I delete the file in Windows (permanently) Unraid still shows it's 51G in size. I've tried using each vDIsk type/bus type.

Edited April 26, 20206 yr by ryley2637

I am afraid that is how vdisks work?     The host does not know that the guest had released space.    Over time a vdisk can be expected to grow to the maximum logical size you assigned to it.

It only shows how much of the disk has been allocated not filled but if you want trim to work on the disk add discard line on your vdisk so trim can be ran on it. 

 

<driver name='qemu' type='raw' cache='writeback' discard='unmap'/>

 

Also note that unmap doesn't work with all vdisk drivers, more info here.