diff --git a/ic-os/hostos/rootfs/opt/ic/share/guestos.xml.template b/ic-os/hostos/rootfs/opt/ic/share/guestos.xml.template
index d3e359d783c..aa2364eec27 100755
--- a/ic-os/hostos/rootfs/opt/ic/share/guestos.xml.template
+++ b/ic-os/hostos/rootfs/opt/ic/share/guestos.xml.template
@@ -38,7 +38,7 @@
   <devices>
     <emulator>/usr/local/bin/qemu-system-x86_64</emulator>
     <disk type='block' device='disk'>
-      <driver name='qemu' type='raw' cache='none'/>
+      <driver name='qemu' type='raw' cache='none' discard='unmap'/>
       <source dev='/dev/hostlvm/guestos' index='1'/>
       <backingStore/>
       <target dev='vda' bus='virtio'/>