Mongodb – sharding + replicating an existing collection

In order for data to be distributed across multiple shards, you need to have multiple chunks for a given sharded collection. A chunk is a contiguous range of shard key values representing approximately 64 megabytes of data by default.

Chunk ranges are normally created automatically based on observation of the shard key values and size of documents being inserted through mongos. When documents are added to a chunk range which is approaching the maximum chunk size, mongos will trigger a chunk split which will try to create smaller logical chunks for balancing.

Currently all data in your sharded testDB.testdata collection is covered by a single chunk on shard0000 (aka your Shard1 server):

    testDB.testData
        shard key: { "name" : 1 }
        chunks:
            shard0000   1
        { "name" : { "$minKey" : 1 } } -->> { "name" : { "$maxKey" : 1 } } on : shard0000 Timestamp(1, 0) 

Using Object.bsonsize() in the mongo shell to determine document size, your sample document in the question is about 43 bytes in BSON. With only 10,000 documents you would not be close to reaching the 64 megabytes of data required to trigger any chunk splits. Something closer to 1.5 million documents of that size would be required.

You will also need to ensure the values for your chosen shard key have reasonable uniqueness. A poor shard key (i.e. with many common values) can lead to indivisible jumbo chunks that cannot be further split.

If you just want to test how sharding works you could:

• insert larger (or more) test documents
• lower the chunk size from the default of 64MB
• pre-split an empty collection before inserting data

issue flushRouterConfig command, and give a try. It enforces mongos to flush cached metadata which is out of date.

Let me know if it doesn't work.