DOCSP-29504-many-to-one-clusters

source/includes/many-with-one-cluster.rst

@@ -0,0 +1,3 @@
+Starting in ``mongosync-beta`` 1.8, you can sync multiple source clusters
+simultaneously with a destination cluster. For example, you can
+consolidate data from many small clusters into a central cluster.

source/includes/migrationName-description.rst

@@ -0,0 +1,4 @@
+Starting in ``mongosync-beta`` 1.8, you can set a migration name for a
+sync operation. For example, you can set a migration name to identify
+each sync operation from multiple source clusters into a destination
+cluster.

source/includes/opts/migrationName.rst

@@ -0,0 +1,18 @@
+.. reference/configuration.txt
+.. reference/mongosync.txt
+
+Starting in ``mongosync-beta`` 1.8, sets a migration name for a sync
+operation. For example, you can set a migration name to identify each
+sync operation from multiple source clusters into one destination
+cluster.
+
+The ``migrationName`` string can contain up to 44 alphanumeric
+and underscore characters. ``migrationName`` is appended to the string
+``"mongosync_internal_"`` to set the migration metadata database name.
+
+If you set ``migrationName`` to
+``"cluster_27000_to_cluster_35000_sync"``, the resulting ``mongosync``
+metadata database name is
+``"mongosync_internal_cluster_27000_to_cluster_35000_sync"``.
+
+For a complete example, see :ref:`c2c-quickstart-many-with-one`.

source/index.txt

@@ -9,7 +9,7 @@ Cluster-to-Cluster Sync
 .. default-domain:: mongodb
 
 {+c2c-product-name+} provides continuous data synchronization or a 
-one-time data migration between two MongoDB clusters. You can enable
+one-time data migration between MongoDB clusters. You can enable
 {+c2c-product-name+} with the :ref:`mongosync <c2c-mongosync>` utility.
 
 ``mongosync`` can continuously synchronize data between two clusters.

source/quickstart.txt

@@ -195,6 +195,8 @@ Initialization Notes
   <c2c-api-start>` command. "cluster0" and "cluster1" are just labels,
   either cluster can be ``cluster0`` or ``cluster1``.
 
+.. _c2c-quickstart-synchronize:
+
 Synchronize Data Between Clusters
 ---------------------------------
 
@@ -305,3 +307,35 @@ Synchronization Notes
 
 - To estimate the size of ``oplog`` needed for initial synchronization,
   see :ref:`c2c-oplog-sizing`.
+
+.. _c2c-quickstart-many-with-one:
+
+Sync Multiple Source Clusters Simultaneously with a Destination Cluster
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. include:: /includes/many-with-one-cluster.rst
+
+For limitations, see :ref:`c2c-limitations_multiple_sync`.
+
+The following examples connect source clusters running on port ``27000``
+and ``27001`` with a destination cluster running on port ``35000``. The
+commands also set the optional :option:`--migrationName` string to
+describe the operations.
+
+.. code-block:: shell
+
+   ./bin/mongosync \
+         --cluster0 "mongodb://localhost:27000" \
+         --cluster1 "mongodb://localhost:35000" \
+         --migrationName "cluster_27000_to_cluster_35000_sync"
+
+   ./bin/mongosync \
+         --cluster0 "mongodb://localhost:27001" \
+         --cluster1 "mongodb://localhost:35000" \
+         --migrationName "cluster_27001_to_cluster_35000_sync"
+
+.. include:: /includes/many-with-one-cluster.rst
+
+To start the sync operation between the source clusters and the
+destination cluster, see the earlier section
+:ref:`c2c-quickstart-synchronize`.

source/reference/configuration.txt

@@ -111,6 +111,15 @@ Options
    To set the ``logPath`` setting from the command line, see the
    :option:`--logPath` option.
 
+.. setting:: migrationName
+
+   *Type*: string
+
+   .. include:: /includes/opts/migrationName.rst
+
+   To set the ``migrationName`` setting from the command line, see the
+   :option:`--migrationName` option.
+
 .. setting:: port
 
    *Type*: integer

source/reference/limitations.txt

@@ -55,6 +55,37 @@ General Limitations
 - ``mongosync`` must read from the source cluster using the 
   :readmode:`primary` read preference.
 
+.. _c2c-limitations_multiple_sync:
+
+Multiple Source Sync Limitations
+--------------------------------
+
+.. include:: /includes/many-with-one-cluster.rst
+
+A namespace is a ``database_name.collection_name`` combination. You can
+only sync namespaces that don't conflict.
+
+For example, consider this scenario:
+
+- Two source clusters S1 and S2.
+- A destination cluster D.
+- Databases named ``inventory`` and ``sales`` on both S1 and S2.
+- Collections named ``products``, ``orderLines``, ``orderStatus``, and
+  ``orders`` on both S1 and S2.
+- You can sync both of these combinations:
+
+  - ``inventory.products`` and ``sales.orderStatus`` on S1 with D.
+  - ``inventory.orderLines`` and ``sales.orders`` on S2 with D.
+
+- You cannot sync both of these combinations because they conflict:
+
+  - ``inventory.products`` and ``inventory.orderLines`` on S1 with D. If
+    D is initially empty, you can sync S1 with D. ``inventory.products``
+    and ``inventory.orderLines`` are copied from S1 to D.
+  - ``inventory.products`` and ``inventory.orderLines`` on S2 with D.
+    You cannot sync S2 with D because ``inventory.products`` and
+    ``inventory.orderLines`` conflict with the namespaces already on D
+    from the scenario in the previous point.
 
 MongoDB Community Edition
 -------------------------

source/reference/mongosync.txt

@@ -119,6 +119,13 @@ Global Options
    .. note:: 
 
       .. include:: /includes/fact-log-rotation-usr1-signal
+
+.. option:: --migrationName <name>
+
+   .. include:: /includes/opts/migrationName.rst
+
+   To set the ``--migrationName`` option from a configuration file,
+   see the :setting:`migrationName` setting.
 
 .. option:: --port
 

source/release-notes/1.8.txt

@@ -21,8 +21,22 @@ Release Notes for mongosync 1.8
 
 **Upcoming**
 
-New Features:
+Beta Features:
 
+Synchronize Data Between Multiple Source Clusters Simultaneously
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. include:: /includes/many-with-one-cluster.rst
+
+Set a Migration Name
+~~~~~~~~~~~~~~~~~~~~
+
+.. include:: /includes/migrationName-description.rst
+
+To set a migration name, see:
+
+- :setting:`migrationName` configuration file setting
+- :option:`--migrationName` command line option
 
 Minimum Supported Version
 -------------------------