diff --git a/nova/volume/driver.py b/nova/volume/driver.py
index 9249918..e468b05 100644
--- a/nova/volume/driver.py
+++ b/nova/volume/driver.py
@@ -107,7 +107,8 @@ class VolumeDriver(object):
                           volume_name, FLAGS.volume_group, run_as_root=True)
 
     def _copy_volume(self, srcstr, deststr, size_in_g):
-        self._execute('dd', 'if=%s' % srcstr, 'of=%s' % deststr,
+        self._execute('ionice', '-c3', 'dd', 'iflag=direct', 'oflag=direct',
+                      'if=%s' % srcstr, 'of=%s' % deststr,
                       'count=%d' % (size_in_g * 1024), 'bs=1M',
                       run_as_root=True)