diff --git a/source/faq.txt b/source/faq.txt index ad7fae829..ef20a57ed 100644 --- a/source/faq.txt +++ b/source/faq.txt @@ -171,3 +171,11 @@ Does ``mongosync`` Support TTL Indexes? {+c2c-product-name+} supports syncing :ref:`index-feature-ttl` from the source to the destination cluster. + +Can I customize chunk distributions when syncing into a sharded cluster? +------------------------------------------------------------------------ + +No, you can't configure ``mongosync`` to customize chunk distributions +on a destination sharded cluster. ``mongosync`` samples each collection +during initialization to determine how to distribute documents +efficiently across the destination cluster’s shards after migration. \ No newline at end of file diff --git a/source/reference/mongosync/mongosync-behavior.txt b/source/reference/mongosync/mongosync-behavior.txt index e83a776dc..8e8c92892 100644 --- a/source/reference/mongosync/mongosync-behavior.txt +++ b/source/reference/mongosync/mongosync-behavior.txt @@ -109,6 +109,19 @@ 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. +Chunk Distribution +'''''''''''''''''' + +``mongosync`` does not preserve chunk distribution from the source to +the destination, even with multiple ``mongosync`` instances. It is not +possible to reproduce a particular pre-split of chunks from a source +cluster on the destination cluster. + +The only sharding configuration that ``mongosync`` preserves from the +source cluster to the destination cluster is the sharding key. Once the +migration finishes, you can enable the destination cluster's balancer which +distributes documents independently of the source cluster's distribution. + Primary Shards ''''''''''''''