diff --git a/linux/HardDiskCaching.sls b/linux/HardDiskCaching.sls
index 4d3a333..af78279 100644
--- a/linux/HardDiskCaching.sls
+++ b/linux/HardDiskCaching.sls
@@ -1,5 +1,6 @@
 # https://lonesysadmin.net/2013/12/22/better-linux-disk-caching-performance-vm-dirty_ratio/
 {% if grains['kernel'] == 'Linux' %}
+  {% if grains['virtual'] == 'kvm' %}
   vm.dirty_background_ratio:
     sysctl.present:
       - value: 10
@@ -18,4 +19,5 @@
   vm.dirty_expire_centisecs:
     sysctl.present:
       - value: 3000
-{% endif %}
+  {% endif %}
+{% endif %}
\ No newline at end of file