I have a newly created Win11 VM and for some reason in the VM it shows that the C-drive is thin provisioned. I prefer thick provisioned as I do not want the VM to fill up my cache drive where the VM disk is located.

 

The disk specification part from the VM specification:

  <devices>
    <emulator>/usr/local/sbin/qemu</emulator>
    <disk type='file' device='disk'>
      <driver name='qemu' type='raw' cache='writeback'/>
      <source file='/mnt/user/domains/Windows11VM/vdisk1.img' index='3'/>
      <backingStore/>
      <target dev='hdc' bus='virtio'/>
      <serial>vdisk1</serial>
      <boot order='1'/>
      <alias name='virtio-disk2'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
    </disk>

How can I change the disk to thick provisioned?

 

Or a better option is to somehow make sure that the disk does not get expanded above the set limit (i.e., 64GB). I started to wonder that does Unraid's VM framework make sure of this?

Edited February 23, 20251 yr by Ruato
Added a question regarding the Unraid's VM framework.

AFAIK, vdisks with Unraid are always thin provisioned.

 

13 hours ago, Ruato said:

make sure that the disk does not get expanded above the set limit (i.e., 64GB)

It should never go above that, though with btrfs for example, wioth time it can use a little more actual disk space due to fragmentation.

Thank you for the information!