Merge "Add specification for Ceph BlueStore Compression"

specs/victoria/approved/ceph-bluestore-compression.rst

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+..
+  Copyright 2020 Canonical Ltd.
+
+  This work is licensed under a Creative Commons Attribution 3.0
+  Unported License.
+  http://creativecommons.org/licenses/by/3.0/legalcode
+
+..
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+  any of the sections in this template.  If you have nothing to say
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+
+==========================
+Ceph BlueStore Compression
+==========================
+
+The Ceph BlueStore storage backend has support for inline compression.
+
+Problem Description
+===================
+
+The Ceph charms currently do not provide documentation, validation or support
+for enabling BlueStore inline compression.
+
+Proposed Change
+===============
+
+Ceph supports configuring compression through per-pool properties and global
+configuration options. What configuration to use depends on the type of data
+and the characteristics of the underlying storage devices in use.
+
+To accomodate this we should allow Ceph consuming charms to configure
+compression on a per-pool basis and have centrally managed defaults for any
+options not provided.
+
+The following configuration options will be added:
+
+* bluestore-compression-algorithm
+
+* bluestore-compression-mode
+
+* bluestore-compression-required-ratio
+
+* bluestore-compression-min-blob-size
+
+* bluestore-compression-min-blob-size-hdd
+
+* bluestore-compression-min-blob-size-ssd
+
+* bluestore-compression-max-blob-size
+
+* bluestore-compression-max-blob-size-hdd
+
+* bluestore-compression-max-blob-size-ssd
+
+Support will be provided for Ceph Mimic and onwards on Ubuntu 18.04 LTS and
+onwards.
+
+Alternatives
+------------
+
+None.
+
+Implementation
+==============
+
+Assignee(s)
+-----------
+
+Primary assignee:
+  fnordahl
+
+Gerrit Topic
+------------
+
+Use Gerrit topic "ceph-bluestore-compression" for all patches related to this
+spec.
+
+.. code-block:: bash
+
+    git-review -t ceph-bluestore-compression
+
+Work Items
+----------
+
+* Extend the Ceph broker API to support providing compression options on pool
+  requests.
+
+* Add context that can be used by both consuming and providing charms to map
+  charm configuration options into CephBrokerRq op properties as well as Jinja2
+  template context data.
+
+* Extend the ``ceph-client`` and ``ceph-rbd-mirror`` reactive interfaces to
+  support relaying compression options for pool creation.
+
+* Add charm configuration options to control global compression defaults to the
+  ceph-osd charm.
+
+* Add charm configuration options to control compression on pool creation to
+  the following charms:
+
+  * glance
+
+  * cinder-ceph
+
+  * nova-compute
+
+  * gnocchi
+
+  * ceph-iscsi
+
+  * ceph-radosgw
+
+* Add support for copying compression properties on pool mirroring to the
+  ceph-rbd-mirror charm.
+
+* Establish a performance baseline and perform benchmark for use in a
+  hyper-converged deployment topology and document results and recommendations.
+
+Repositories
+------------
+
+No new repositories are required to implement this spec.
+
+Documentation
+-------------
+
+The individual configuration options will get a description that explains basic
+usage.
+
+A new appendix or section should be added to the deployment-guide to document
+results of benchmark and recommendations for deployment of Ceph with BlueStore
+Compression.
+
+Security
+--------
+
+Apart from enabling code paths in Ceph that was previously not exposed in the
+charms, there are no security specific considerations for this feature work.
+
+Testing
+-------
+
+Existing charm gates should be extended to validate the operation of the new
+charm configuration options.
+
+No special hardware is required to validate the feature.
+
+Dependencies
+============
+
+None.