diff --git a/src/sbin/livemedia-creator b/src/sbin/livemedia-creator
index 7b698a4e..fd8f55fa 100755
--- a/src/sbin/livemedia-creator
+++ b/src/sbin/livemedia-creator
@@ -141,7 +141,7 @@ class VirtualInstall(object):
             args.append(ks)
 
         disk_opts = "path={0}".format(disk_img)
-        disk_opts += ",cache=unsafe"
+        disk_opts += ",cache=unsafe,discard=unmap"
         if qcow2:
             disk_opts += ",format=qcow2"
         else: