diff --git a/source/reference/api/start.txt b/source/reference/api/start.txt index 0fa2ddf98..4b693d5ba 100644 --- a/source/reference/api/start.txt +++ b/source/reference/api/start.txt @@ -359,14 +359,6 @@ State If the ``start`` request is successful, ``mongosync`` enters the ``RUNNING`` state. -Pre-Split Chunks -~~~~~~~~~~~~~~~~ - -When ``mongosync`` syncs to a sharded destination cluster, it pre-splits chunks -for sharded collections on the destination cluster. For each sharded collection, -``mongosync`` creates twice as many chunks as there are shards in the -destination cluster. - .. _c2c-shard-replica-sets: Shard Replica Sets @@ -379,6 +371,9 @@ collections. The ``sharding.shardingEntries`` array specifies the collections to shard. Collections that are not listed in this array replicate as unsharded. +For more information, see :ref:`Sharded Cluster Behavior +`. + .. _c2c-supporting-index-behavior: Supporting Indexes diff --git a/source/reference/mongosync/mongosync-behavior.txt b/source/reference/mongosync/mongosync-behavior.txt index 0b431ca67..a108af8fd 100644 --- a/source/reference/mongosync/mongosync-behavior.txt +++ b/source/reference/mongosync/mongosync-behavior.txt @@ -54,19 +54,36 @@ For information on available settings, see :ref:`Configuration `. Cluster and Collection Types ---------------------------- +.. _c2c-sharded-cluster-behavior: + Sharded Clusters ~~~~~~~~~~~~~~~~ {+c2c-product-name+} supports replication between sharded clusters. -Individual shards are replicated in parallel from the source cluster to -the destination cluster, however a :ref:`chunk migration -` or similar source update could move -documents to a new source shard during replication. +``mongosync`` replicates individual shards in parallel from the source +cluster to the destination cluster. However ``mongosync`` does not +preserve the source cluster's sharding configuration. + +Pre-Split Chunks +'''''''''''''''' + +When ``mongosync`` syncs to a sharded destination cluster, it pre-splits chunks +for sharded collections on the destination cluster. For each sharded collection, +``mongosync`` creates twice as many chunks as there are shards in the +destination cluster. + +Primary Shards +'''''''''''''' -Even if documents move between source shards during replication, -{+c2c-product-name+} maintains the :term:`eventual consistency` -guarantee on the destination cluster. For more information, see -:ref:`c2c-sharded-clusters`. +When you sync to a sharded destination cluster, ``mongosync`` assigns a +primary shard to each database by means of a round-robin. + +.. warning:: + + Running :dbcommand:`movePrimary` on the source or desintation cluster + during migration may result in a fatal error or require you to + restart the migration from the start. For more information, see + :ref:`c2c-sharded-limitations`. Multiple Clusters ~~~~~~~~~~~~~~~~~ @@ -162,13 +179,6 @@ snapshot of the source data. To learn more, see :ref:`c2c-behavior-consistency`. Otherwise, start a new continuous sync operation by using a new empty destination cluster. -Sharded Clusters -~~~~~~~~~~~~~~~~ - -When running continuous sync with sharded clusters, you must stop -:ref:`balancers ` on both the source and the destination -for the lifetime of the sync until commit. - Temporary Changes to Collection Characteristics ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~