Merge "Set LVM driver default overprovisioning ratio to 1.0"

cinder/tests/unit/test_volume.py

@@ -6612,6 +6612,7 @@ class GenericVolumeDriverTestCase(DriverTestCase):
         db.volume_destroy(self.context, dest_vol['id'])
 
 
+@ddt.ddt
 class LVMVolumeDriverTestCase(DriverTestCase):
     """Test case for VolumeDriver"""
     driver_name = "cinder.volume.drivers.lvm.LVMVolumeDriver"
@@ -7367,6 +7368,26 @@ class LVMVolumeDriverTestCase(DriverTestCase):
         ret = self.volume.driver.unmanage(volume)
         self.assertIsNone(ret)
 
+    # Global setting, LVM setting, expected outcome
+    @ddt.data((10.0, 2.0, 2.0))
+    @ddt.data((10.0, None, 10.0))
+    @ddt.unpack
+    def test_lvm_max_over_subscription_ratio(self,
+                                             global_value,
+                                             lvm_value,
+                                             expected_value):
+        configuration = conf.Configuration(fake_opt, 'fake_group')
+        configuration.max_over_subscription_ratio = global_value
+        configuration.lvm_max_over_subscription_ratio = lvm_value
+
+        fake_vg = mock.Mock(fake_lvm.FakeBrickLVM('cinder-volumes', False,
+                                                  None, 'default'))
+        lvm_driver = lvm.LVMVolumeDriver(configuration=configuration,
+                                         vg_obj=fake_vg, db=db)
+
+        self.assertEqual(expected_value,
+                         lvm_driver.configuration.max_over_subscription_ratio)
+
 
 class ISCSITestCase(DriverTestCase):
     """Test Case for ISCSIDriver"""

cinder/volume/drivers/lvm.py

@@ -60,7 +60,15 @@ volume_opts = [
                help='LVM conf file to use for the LVM driver in Cinder; '
                     'this setting is ignored if the specified file does '
                     'not exist (You can also specify \'None\' to not use '
-                    'a conf file even if one exists).')
+                    'a conf file even if one exists).'),
+    cfg.FloatOpt('lvm_max_over_subscription_ratio',
+                 # This option exists to provide a default value for the
+                 # LVM driver which is different than the global default.
+                 default=1.0,
+                 help='max_over_subscription_ratio setting for the LVM '
+                      'driver.  If set, this takes precedence over the '
+                      'general max_over_subscription_ratio option.  If '
+                      'None, the general option is used.')
 ]
 
 CONF = cfg.CONF
@@ -101,6 +109,10 @@ class LVMVolumeDriver(driver.VolumeDriver):
         self.protocol = self.target_driver.protocol
         self._sparse_copy_volume = False
 
+        if self.configuration.lvm_max_over_subscription_ratio is not None:
+            self.configuration.max_over_subscription_ratio = \
+                self.configuration.lvm_max_over_subscription_ratio
+
     def _sizestr(self, size_in_g):
         return '%sg' % size_in_g