Reference: fate#315125: Set NOCOW flag to newly created volume by default, to solve performance issue on btrfs. Signed-off-by: Chunyan Liu Index: virt-manager-1.4.2/virtinst/storage.py =================================================================== --- virt-manager-1.4.2.orig/virtinst/storage.py +++ virt-manager-1.4.2/virtinst/storage.py @@ -708,6 +708,12 @@ class StorageVolume(_StorageObject): return self._pool_xml.get_disk_type() file_type = property(_get_vol_type) + def _nocow_default_cb(self): + return self.conn.check_support( + self.conn.SUPPORT_CONN_NOCOW) + nocow = XMLProperty("./target/nocow", + is_bool=True, default_cb=_nocow_default_cb) + ################## # XML properties # Index: virt-manager-1.4.2/virtinst/support.py =================================================================== --- virt-manager-1.4.2.orig/virtinst/support.py +++ virt-manager-1.4.2/virtinst/support.py @@ -324,6 +324,8 @@ SUPPORT_CONN_RNG_URANDOM = _make(version SUPPORT_CONN_USB3_PORTS = _make(version="1.3.5") SUPPORT_CONN_MACHVIRT_PCI_DEFAULT = _make(version="3.0.0") SUPPORT_CONN_QEMU_XHCI = _make(version="3.3.0") +SUPPORT_CONN_NOCOW = _make( + version="1.2.18", hv_version={"qemu": "2.2.0", "test": 0}) # This is for disk . xen supports this, but it's