openstack/fuel-docs
Code Issues Proposed changes

Merge "Correct description of use_cow setting" into stable/6.0

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2015-07-10 12:20:04 +00:00
committed by Gerrit Code Review
parent 7cfa3b1910 50358e43d7
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19
pages/user-guide/config-environment/settings/3400-qcow.rst
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@@ -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: 90%
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.