openstack/fuel-docs
Code Issues Proposed changes

Correct description of use_cow setting

Browse Source 
The previous description of this setting was inaccurate.
This setting refers to how ephemeral drives are handled
by Nova.

Change-Id: Ic9a534554d8cb920a38265b449e8e94984bfa28c
Closes-bug: #1375899
This commit is contained in:
Ryan Moe
2015-02-17 15:18:37 -08:00
parent 1d7060b7f0
commit e6050003d0
1 changed files with 7 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
pages/user-guide/config-environment/settings/3400-qcow.rst
View File

@@ -4,19 +4,14 @@
Choose image format
+++++++++++++++++++
Choose whether to use the qcow2 image format for saved images.
Select image format for ephemeral storage.
.. image:: /_images/user_screen_shots/qcow.png
:width: 110%
This selects the image format used for :ref:`Glance<glance-term>`
and :ref:`ephemeral volumes<ephemeral-storage-term>`.
The default setting is to use
the qcow (actually :ref:`qcow2<qcow2-term>`) format,
which is recommended when using :ref:`Swift<swift-object-storage-term>`
as the storage backend for Glance.
If you use :ref:`Ceph RBD<ceph-term>`
for Glance image storage or for ephemeral volumes,
you should disable the qcow image format
so that the raw format is used.
When this option is selected, :ref:`ephemeral volumes<ephemeral-storage-term>`
will be created as a copy-on-write layer of the base image.
Without this option selected, ephemeral volumes will be full
copies of the base image. The default setting is to use
copy-on-write for ephemeral volumes. This option has no effect
when using :ref:`Ceph<ceph-term>` for ephemeral storage.