openstack
/
nova
Code Issues Proposed changes

libvirt: vzstorage: Use 'writeback' QEMU cache mode 

The 'writethrough' cache mode is terribly slow.  Use the saner
alternative, "writeback" cache mode.

See further details in the documentation of change Ibe236988af2
("libvirt: Use 'writeback' QEMU cache mode when 'none' is not viable).

Related-Bug: #1818847

Change-Id: I5aae681bc8e8feb7703a89f91b942360dd69c35d
Signed-off-by: Kashyap Chamarthy <kchamart@redhat.com>
This commit is contained in:
Kashyap Chamarthy 2019-03-14 14:28:12 +01:00
parent b9dc86d8d6
commit 44edfa045c
2 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
nova/tests/unit/virt/libvirt/volume/test_vzstorage.py
View File

@ -110,4 +110,4 @@ class LibvirtVZStorageTestCase(test_volume.LibvirtVolumeBaseTestCase):
self.assertEqual('file', conf.source_type)
self.assertEqual(file_path, conf.source_path)
self.assertEqual('raw', conf.driver_format)
self.assertEqual('writethrough', conf.driver_cache)
self.assertEqual('writeback', conf.driver_cache)

2
nova/virt/libvirt/volume/vzstorage.py
View File

@ -71,7 +71,7 @@ class LibvirtVZStorageVolumeDriver(fs.LibvirtBaseFileSystemVolumeDriver):
self).get_config(connection_info, disk_info)
conf.source_type = 'file'
conf.driver_cache = 'writethrough'
conf.driver_cache = 'writeback'
conf.source_path = connection_info['data']['device_path']
conf.driver_format = connection_info['data'].get('format', 'raw')
return conf