openstack/cinder
Code Issues Proposed changes

NetApp ONTAP: Fix reporting of provisioned_capacity_gb

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The ONTAP drivers in Cinder ("7mode" and "cmode") cannot
reliably and efficiently track provisioned_capacity_gb as expected
by the Cinder scheduler.

The driver authors originally assumed that provisioned_capacity_gb
is consumed space on the backend. This results in miscalculation of
over subscription in the Cinder scheduler.

The fix adopted here is to remove this wrong reporting and rely on
calculation of the provisioned_capacity_gb in the scheduler.

Change-Id: Ic106dbcae8ceaac265b710756ab1874e445ca826
Closes-Bug: #1714209
This commit is contained in:
Goutham Pacha Ravi 2017-09-13 23:54:08 -06:00 committed by Ben Swartzlander
parent 6c236bca3d
commit 42b8b7fe60
9 changed files with 16 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
cinder/tests/unit/volume/drivers/netapp/dataontap/fakes.py
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@ -378,7 +378,6 @@ FAKE_7MODE_POOLS = [
'multiattach': False,
'thin_provisioning_support': False,
'thick_provisioning_support': True,
'provisioned_capacity_gb': 0.0,
'utilization': 30.0,
'filter_function': 'filter',
'goodness_function': 'goodness',

1
cinder/tests/unit/volume/drivers/netapp/dataontap/test_block_7mode.py
View File

@ -578,7 +578,6 @@ class NetAppBlockStorage7modeLibraryTestCase(test.TestCase):
'QoS_support': False,
'thin_provisioning_support': not thick,
'thick_provisioning_support': thick,
'provisioned_capacity_gb': 2.94,
'free_capacity_gb': 1339.27,
'total_capacity_gb': 1342.21,
'reserved_percentage': 5,

1
cinder/tests/unit/volume/drivers/netapp/dataontap/test_block_cmode.py
View File

@ -412,7 +412,6 @@ class NetAppBlockStorageCmodeLibraryTestCase(test.TestCase):
'multiattach': False,
'total_capacity_gb': 10.0,
'free_capacity_gb': 2.0,
'provisioned_capacity_gb': 8.0,
'netapp_dedupe_used_percent': 55.0,
'netapp_aggregate_used_percent': 45,
'utilization': 30.0,

3
cinder/tests/unit/volume/drivers/netapp/dataontap/test_nfs_7mode.py
View File

@ -100,13 +100,11 @@ class NetApp7modeNfsDriverTestCase(test.TestCase):
fake.TOTAL_BYTES // units.Gi, '0.01')
free_capacity_gb = na_utils.round_down(
fake.AVAILABLE_BYTES // units.Gi, '0.01')
provisioned_capacity_gb = total_capacity_gb - free_capacity_gb
capacity = {
'reserved_percentage': fake.RESERVED_PERCENTAGE,
'max_over_subscription_ratio': fake.MAX_OVER_SUBSCRIPTION_RATIO,
'total_capacity_gb': total_capacity_gb,
'free_capacity_gb': free_capacity_gb,
'provisioned_capacity_gb': provisioned_capacity_gb,
}
self.mock_object(self.driver,
'_get_share_capacity_info',
@ -128,7 +126,6 @@ class NetApp7modeNfsDriverTestCase(test.TestCase):
'reserved_percentage': 7,
'max_over_subscription_ratio': 19.0,
'multiattach': False,
'provisioned_capacity_gb': 4456.0,
'utilization': 30.0,
'filter_function': 'filter',
'goodness_function': 'goodness'}]

3
cinder/tests/unit/volume/drivers/netapp/dataontap/test_nfs_cmode.py
View File

@ -179,13 +179,11 @@ class NetAppCmodeNfsDriverTestCase(test.TestCase):
fake.TOTAL_BYTES // units.Gi, '0.01')
free_capacity_gb = na_utils.round_down(
fake.AVAILABLE_BYTES // units.Gi, '0.01')
provisioned_capacity_gb = total_capacity_gb - free_capacity_gb
capacity = {
'reserved_percentage': fake.RESERVED_PERCENTAGE,
'max_over_subscription_ratio': fake.MAX_OVER_SUBSCRIPTION_RATIO,
'total_capacity_gb': total_capacity_gb,
'free_capacity_gb': free_capacity_gb,
'provisioned_capacity_gb': provisioned_capacity_gb,
}
self.mock_object(self.driver,
'_get_share_capacity_info',
@ -219,7 +217,6 @@ class NetAppCmodeNfsDriverTestCase(test.TestCase):
'multiattach': False,
'total_capacity_gb': total_capacity_gb,
'free_capacity_gb': free_capacity_gb,
'provisioned_capacity_gb': provisioned_capacity_gb,
'netapp_dedupe_used_percent': 55.0,
'netapp_aggregate_used_percent': 45,
'utilization': 30.0,

3
cinder/volume/drivers/netapp/dataontap/block_7mode.py
View File

@ -341,9 +341,6 @@ class NetAppBlockStorage7modeLibrary(block_base.NetAppBlockStorageLibrary):
free /= units.Gi
pool['free_capacity_gb'] = na_utils.round_down(free, '0.01')
pool['provisioned_capacity_gb'] = (round(
pool['total_capacity_gb'] - pool['free_capacity_gb'], 2))
thick = (
self.configuration.netapp_lun_space_reservation == 'enabled')
pool['thick_provisioning_support'] = thick

3
cinder/volume/drivers/netapp/dataontap/block_cmode.py
View File

@ -311,9 +311,6 @@ class NetAppBlockStorageCmodeLibrary(block_base.NetAppBlockStorageLibrary,
size_available_gb = capacity['size-available'] / units.Gi
pool['free_capacity_gb'] = na_utils.round_down(size_available_gb)
pool['provisioned_capacity_gb'] = round(
pool['total_capacity_gb'] - pool['free_capacity_gb'], 2)
if self.using_cluster_credentials:
dedupe_used = self.zapi_client.get_flexvol_dedupe_used_percent(
ssc_vol_name)

2
cinder/volume/drivers/netapp/dataontap/nfs_base.py
View File

@ -885,8 +885,6 @@ class NetAppNfsDriver(driver.ManageableVD,
total_size / units.Gi)
capacity['free_capacity_gb'] = na_utils.round_down(
total_available / units.Gi)
capacity['provisioned_capacity_gb'] = (round(
capacity['total_capacity_gb'] - capacity['free_capacity_gb'], 2))
return capacity

16
releasenotes/notes/bug-1714209-netapp-ontap-drivers-oversubscription-issue-c4655b9c4858d7c6.yaml Normal file
View File

@ -0,0 +1,16 @@
---
fixes:
- The ONTAP drivers ("7mode" and "cmode") have been fixed to not report
consumed space as "provisioned_capacity_gb". They instead rely on
the cinder scheduler's calculation of "provisioned_capacity_gb". This
fixes the oversubscription miscalculations with the ONTAP drivers. This
bugfix affects all three protocols supported by these drivers
(iSCSI/FC/NFS).
upgrade:
- If using the NetApp ONTAP drivers (7mode/cmode), the configuration value
for "max_over_subscription_ratio" may need to be increased to
avoid scheduling problems where storage pools that previously were
valid to schedule new volumes suddenly appear to be out of space
to the Cinder scheduler. See
documentation `here <https://docs.openstack
.org/cinder/latest/admin/blockstorage-over-subscription.html>`_.