diff --git a/nova/scheduler/host_manager.py b/nova/scheduler/host_manager.py
index 33ba2c160..695189881 100644
--- a/nova/scheduler/host_manager.py
+++ b/nova/scheduler/host_manager.py
@@ -122,7 +122,10 @@ class HostState(object):
         all_disk_mb = compute['local_gb'] * 1024
         all_ram_mb = compute['memory_mb']
 
-        free_disk_mb = compute['free_disk_gb'] * 1024
+        # Assume virtual size is all consumed by instances if use qcow2 disk.
+        least = compute.get('disk_available_least')
+        free_disk_mb = least if least is not None else compute['free_disk_gb']
+        free_disk_mb *= 1024
         free_ram_mb = compute['free_ram_mb']
 
         if FLAGS.reserved_host_disk_mb > 0:
diff --git a/nova/tests/scheduler/fakes.py b/nova/tests/scheduler/fakes.py
index e48e987a4..27341a62c 100644
--- a/nova/tests/scheduler/fakes.py
+++ b/nova/tests/scheduler/fakes.py
@@ -27,17 +27,17 @@ from nova.scheduler import host_manager
 
 COMPUTE_NODES = [
         dict(id=1, local_gb=1024, memory_mb=1024, vcpus=1,
-                free_disk_gb=512, free_ram_mb=512, vcpus_used=1,
-                service=dict(host='host1', disabled=False)),
+             disk_available_least=512, free_ram_mb=512, vcpus_used=1,
+             free_disk_mb=512, service=dict(host='host1', disabled=False)),
         dict(id=2, local_gb=2048, memory_mb=2048, vcpus=2,
-                free_disk_gb=1024, free_ram_mb=1024, vcpus_used=2,
-                service=dict(host='host2', disabled=True)),
+             disk_available_least=1024, free_ram_mb=1024, vcpus_used=2,
+             free_disk_mb=1024, service=dict(host='host2', disabled=True)),
         dict(id=3, local_gb=4096, memory_mb=4096, vcpus=4,
-                free_disk_gb=3072, free_ram_mb=3072, vcpus_used=1,
-                service=dict(host='host3', disabled=False)),
+             disk_available_least=3072, free_ram_mb=3072, vcpus_used=1,
+             free_disk_mb=3072, service=dict(host='host3', disabled=False)),
         dict(id=4, local_gb=8192, memory_mb=8192, vcpus=8,
-                free_disk_gb=8192, free_ram_mb=8192, vcpus_used=0,
-                service=dict(host='host4', disabled=False)),
+             disk_available_least=8192, free_ram_mb=8192, vcpus_used=0,
+             free_disk_mb=8192, service=dict(host='host4', disabled=False)),
         # Broken entry
         dict(id=5, local_gb=1024, memory_mb=1024, vcpus=1, service=None),
 ]
diff --git a/nova/tests/scheduler/test_filter_scheduler.py b/nova/tests/scheduler/test_filter_scheduler.py
index 1cab6ebbf..a18c0e678 100644
--- a/nova/tests/scheduler/test_filter_scheduler.py
+++ b/nova/tests/scheduler/test_filter_scheduler.py
@@ -203,8 +203,8 @@ class FilterSchedulerTestCase(test_scheduler.SchedulerTestCase):
         self.assertEquals(weight, -1.0)
         hostinfo = host_manager.HostState('host', 'compute')
         hostinfo.update_from_compute_node(dict(memory_mb=1000,
-                local_gb=0, vcpus=1, free_disk_gb=1000, free_ram_mb=1000,
-                vcpus_used=0))
+                local_gb=0, vcpus=1, disk_available_least=1000,
+                free_disk_mb=1000, free_ram_mb=1000, vcpus_used=0))
         self.assertEquals(1000 - 128, fn(hostinfo, {}))
 
     def test_max_attempts(self):