52370e58fe
These are in the cinder doc tree so of course they're block storage-related. Change-Id: Ic1950ff89021a89de397619eef17f8100eb3d847 Signed-off-by: Stephen Finucane <stephenfin@redhat.com>
60 lines
2.3 KiB
ReStructuredText
60 lines
2.3 KiB
ReStructuredText
.. _accelerate_image_compression:
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============================
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Accelerate image compression
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============================
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A general framework to accommodate hardware compression accelerators for
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compression of volumes uploaded to the Image service (Glance) as images and
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decompression of compressed images used to create volumes is introduced in
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Train release.
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The only accelerator supported in this release is Intel QuickAssist Technology
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(QAT), which produces a compressed file in gzip format. Additionally, the
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framework provides software-based compression using GUNzip tool if a suitable
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hardware accelerator is not available. Because this software fallback could
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cause performance problems if the Cinder services are not deployed on
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sufficiently powerful nodes, the default setting is *not* to enable compression
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on image upload or download.
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The compressed image of a volume will be stored in the Image service (Glance)
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with the ``container_format`` image property of ``compressed``. See the `Image
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service documentation <https://docs.openstack.org/glance/latest>`_ for more
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information about this image container format.
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Configure image compression
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~~~~~~~~~~~~~~~~~~~~~~~~~~~
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To enable the image compression feature, set the following configuration option
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in the ``cinder.conf`` file:
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.. code-block:: ini
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allow_compression_on_image_upload = True
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By default it will be set to False, which means image compression is disabled.
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.. code-block:: ini
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compression_format = gzip
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This is to specify image compression format. The only supported format is
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``gzip`` in Train release.
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System requirement
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~~~~~~~~~~~~~~~~~~
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In order to use this feature, there should be a hardware accelerator existing
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in system, otherwise no benefit will get from this feature. Regarding the two
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accelerators that supported, system should be configured as below:
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- ``Intel QuickAssist Technology (QAT)`` - This is the hardware accelerator
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from Intel. The driver of QAT should be installed, refer to
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https://01.org/intel-quickassist-technology. Also the compression library
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QATzip should be installed, refer to https://github.com/intel/QATzip.
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- ``GUNzip`` - The related package of ``GUNzip`` should be installed and the
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command ``gzip`` should be available. This is used as fallback when hardware
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accelerator is not available.
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