From 50358e43d7e8cc2f2e4eb6007395b9a363cff691 Mon Sep 17 00:00:00 2001 From: Ryan Moe Date: Tue, 17 Feb 2015 15:18:37 -0800 Subject: [PATCH] Correct description of use_cow setting 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 (cherry picked from commit e6050003d0265f1a5ab2dac2bf81eb21e56cd862) --- .../config-environment/settings/3400-qcow.rst | 19 +++++++------------ 1 file changed, 7 insertions(+), 12 deletions(-) diff --git a/pages/user-guide/config-environment/settings/3400-qcow.rst b/pages/user-guide/config-environment/settings/3400-qcow.rst index 250e444b6..a2af7c6b5 100644 --- a/pages/user-guide/config-environment/settings/3400-qcow.rst +++ b/pages/user-guide/config-environment/settings/3400-qcow.rst @@ -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` -and :ref:`ephemeral volumes`. -The default setting is to use -the qcow (actually :ref:`qcow2`) format, -which is recommended when using :ref:`Swift` -as the storage backend for Glance. -If you use :ref:`Ceph RBD` -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` +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` for ephemeral storage.