=cls #17846 Add experimental note to ddata mode docs

akka-cluster-sharding/src/main/resources/reference.conf

@@ -68,6 +68,8 @@ akka.cluster.sharding {
 
   # Parameter which determines how the coordinator will be store a state
   # valid values either "persistence" or "ddata"
+  # The "ddata" mode is experimental, since it depends on the experimental
+  # module akka-distributed-data-experimental.
   state-store-mode = "persistence"
 
   # The shard saves persistent snapshots after this number of persistent

akka-docs/rst/java/cluster-sharding.rst

@@ -179,14 +179,22 @@ shard resolution, e.g. to avoid too fine grained shards.
 Distributed Data Mode
 ---------------------
 
-Instead of using ``akka-persistence`` is possible to use ``akka-distributed-data`` module. In such case
+Instead of using :ref:`persistence-java` it is possible to use the :ref:`distributed_data_java` module
-state of the ``ShardCoordinator`` will be replicated inside a cluster by the ``akka-distributed-data``
+as storage for the state of the sharding coordinator. In such case the state of the 
-module with the ``WriteMajority`` consistency. This mode could be enabled by setting up
+``ShardCoordinator`` will be replicated inside a cluster by the Distributed Data module with
-``akka.cluster.sharding.state-store-mode`` as ``ddata``.
+``WriteMajority``/``ReadMajority`` consistency.
-It make possible to remove ``akka-persistence`` dependency from a project if this dependency
+
-has not using in user code and ``remember-entities`` is ``off``.
+This mode can be enabled by setting configuration property ``akka.cluster.sharding.state-store-mode``
-Note that option also could lead to the shards duplication in case of a cluster fragmentation
+as ``ddata``. 
-due to a broken replication between nodes.
+
+You must explicitly add the ``akka-distributed-data-experimental`` dependency to your build if
+you use this mode. It is possible to remove ``akka-persistence`` dependency from a project if it
+is not used in user code and ``remember-entities`` is ``off``.
+
+.. warning::
+
+  The ``ddata`` mode is considered as **“experimental”** as of its introduction in Akka 2.4.0, since
+  it depends on the experimental Distributed Data module.
 
 Proxy Only Mode
 ---------------

akka-docs/rst/scala/cluster-sharding.rst

@@ -182,14 +182,22 @@ shard resolution, e.g. to avoid too fine grained shards.
 Distributed Data Mode
 ---------------------
 
-Instead of using ``akka-persistence`` is possible to use ``akka-distributed-data`` module. In such case
+Instead of using :ref:`persistence-scala` it is possible to use the :ref:`distributed_data_scala` module
-state of the ``ShardCoordinator`` will be replicated inside a cluster by the ``akka-distributed-data``
+as storage for the state of the sharding coordinator. In such case the state of the 
-module with the ``WriteMajority`` consistency. This mode could be enabled by setting up
+``ShardCoordinator`` will be replicated inside a cluster by the Distributed Data module with
-``akka.cluster.sharding.state-store-mode`` as ``ddata``.
+``WriteMajority``/``ReadMajority`` consistency.
-It make possible to remove ``akka-persistence`` dependency from a project if this dependency
+
-has not using in user code and ``remember-entities`` is ``off``.
+This mode can be enabled by setting configuration property ``akka.cluster.sharding.state-store-mode``
-Note that option also could lead to the shards duplication in case of a cluster fragmentation
+as ``ddata``. 
-due to a broken replication between nodes.
+
+You must explicitly add the ``akka-distributed-data-experimental`` dependency to your build if
+you use this mode. It is possible to remove ``akka-persistence`` dependency from a project if it
+is not used in user code and ``remember-entities`` is ``off``.
+
+.. warning::
+
+  The ``ddata`` mode is considered as **“experimental”** as of its introduction in Akka 2.4.0, since
+  it depends on the experimental Distributed Data module.
 
 Proxy Only Mode
 ---------------