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+===========
+Compression
+===========
+
+.. versionadded:: Kraken
+
+The Ceph Object Gateway supports server-side compression of uploaded objects,
+using any of Ceph's existing compression plugins.
+
+
+Configuration
+=============
+
+Compression can be enabled on a storage class in the Zone's placement target
+by providing the ``--compression=<type>`` option to the command
+``radosgw-admin zone placement modify``.
+
+The compression ``type`` refers to the name of the compression plugin to use
+when writing new object data. Each compressed object remembers which plugin
+was used, so changing this setting does not hinder the ability to decompress
+existing objects, not does it force existing objects to be recompressed.
+
+This compression setting applies to all new objects uploaded to buckets using
+this placement target. Compression can be disabled by setting the ``type`` to
+an empty string or ``none``.
+
+For example::
+
+  $ radosgw-admin zone placement modify \
+        --rgw-zone default \
+        --placement-id default-placement \
+        --storage-class STANDARD \
+        --compression zlib
+  {
+  ...
+      "placement_pools": [
+          {
+              "key": "default-placement",
+              "val": {
+                  "index_pool": "default.rgw.buckets.index",
+                  "storage_classes": {
+                      "STANDARD": {
+                          "data_pool": "default.rgw.buckets.data",
+                          "compression_type": "zlib"
+                      }
+                  },
+                  "data_extra_pool": "default.rgw.buckets.non-ec",
+                  "index_type": 0,
+              }
+          }
+      ],
+  ...
+  }
+
+.. note:: A ``default`` zone is created for you if you have not done any
+   previous `Multisite Configuration`_.
+
+
+Statistics
+==========
+
+While all existing commands and APIs continue to report object and bucket
+sizes based their uncompressed data, compression statistics for a given bucket
+are included in its ``bucket stats``::
+
+  $ radosgw-admin bucket stats --bucket=<name>
+  {
+  ...
+      "usage": {
+          "rgw.main": {
+              "size": 1075028,
+              "size_actual": 1331200,
+              "size_utilized": 592035,
+              "size_kb": 1050,
+              "size_kb_actual": 1300,
+              "size_kb_utilized": 579,
+              "num_objects": 104
+          }
+      },
+  ...
+  }
+
+The ``size_utilized`` and ``size_kb_utilized`` fields represent the total
+size of compressed data, in bytes and kilobytes respectively.
+
+
+.. _`Multisite Configuration`: ../multisite