diff --git a/nova/scheduler/host_manager.py b/nova/scheduler/host_manager.py
index 8fab6ea0e4..43d7db9e61 100644
--- a/nova/scheduler/host_manager.py
+++ b/nova/scheduler/host_manager.py
@@ -183,8 +183,15 @@ class HostState(object):
         all_ram_mb = compute['memory_mb']
 
         # 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_gb = compute.get('free_disk_gb')
+        least_gb = compute.get('disk_available_least')
+        if least_gb > free_gb and free_gb:
+            # can occur when an instance in database is not on host
+            LOG.warn(_("Host has more disk space than database expected"
+                       " (%(physical)sgb > %(database)sgb)") %
+                     {'physical': least_gb, 'database': free_gb})
+        free_disk_mb = min(val for val in [least_gb,
+                                           free_gb] if val is not None)
         free_disk_mb *= 1024
 
         self.disk_mb_used = compute['local_gb_used'] * 1024
diff --git a/nova/tests/scheduler/fakes.py b/nova/tests/scheduler/fakes.py
index 6d020c7603..6cb91a9f55 100644
--- a/nova/tests/scheduler/fakes.py
+++ b/nova/tests/scheduler/fakes.py
@@ -27,26 +27,26 @@ from nova.scheduler import host_manager
 
 COMPUTE_NODES = [
         dict(id=1, local_gb=1024, memory_mb=1024, vcpus=1,
-             disk_available_least=512, free_ram_mb=512, vcpus_used=1,
-             free_disk_mb=512, local_gb_used=0, updated_at=None,
+             disk_available_least=None, free_ram_mb=512, vcpus_used=1,
+             free_disk_gb=512, local_gb_used=0, updated_at=None,
              service=dict(host='host1', disabled=False),
              hypervisor_hostname='node1', host_ip='127.0.0.1',
              hypervisor_version=0),
         dict(id=2, local_gb=2048, memory_mb=2048, vcpus=2,
              disk_available_least=1024, free_ram_mb=1024, vcpus_used=2,
-             free_disk_mb=1024, local_gb_used=0, updated_at=None,
+             free_disk_gb=None, local_gb_used=0, updated_at=None,
              service=dict(host='host2', disabled=True),
              hypervisor_hostname='node2', host_ip='127.0.0.1',
              hypervisor_version=0),
         dict(id=3, local_gb=4096, memory_mb=4096, vcpus=4,
-             disk_available_least=3072, free_ram_mb=3072, vcpus_used=1,
-             free_disk_mb=3072, local_gb_used=0, updated_at=None,
+             disk_available_least=3333, free_ram_mb=3072, vcpus_used=1,
+             free_disk_gb=3072, local_gb_used=0, updated_at=None,
              service=dict(host='host3', disabled=False),
              hypervisor_hostname='node3', host_ip='127.0.0.1',
              hypervisor_version=0),
         dict(id=4, local_gb=8192, memory_mb=8192, vcpus=8,
              disk_available_least=8192, free_ram_mb=8192, vcpus_used=0,
-             free_disk_mb=8192, local_gb_used=0, updated_at=None,
+             free_disk_gb=8888, local_gb_used=0, updated_at=None,
              service=dict(host='host4', disabled=False),
              hypervisor_hostname='node4', host_ip='127.0.0.1',
              hypervisor_version=0),
diff --git a/nova/tests/scheduler/test_host_manager.py b/nova/tests/scheduler/test_host_manager.py
index e81e909f5f..17cd06cc4c 100644
--- a/nova/tests/scheduler/test_host_manager.py
+++ b/nova/tests/scheduler/test_host_manager.py
@@ -274,6 +274,9 @@ class HostManagerTestCase(test.NoDBTestCase):
         self.mox.StubOutWithMock(host_manager.LOG, 'warn')
 
         db.compute_node_get_all(context).AndReturn(fakes.COMPUTE_NODES)
+        # node 3 host physical disk space is greater than database
+        host_manager.LOG.warn("Host has more disk space than database expected"
+                              " (3333gb > 3072gb)")
         # Invalid service
         host_manager.LOG.warn("No service for compute ID 5")