MongoDB Documentation, Release 3.0.4 Step 5: Shard the collection. In the test database, shard the test_collection , specifying number as the shard key. use test sh.shardCollection( "test.test_collection", { "number" : 1 } ) The method returns the status of the operation: { "collectionsharded" : "test.test_collection", "ok" : 1 } The balancer (page 684) will redistribute chunks of documents when it next runs. As clients insert additional docu- ments into this collection, the mongos will route the documents between the shards. Step 6: Confirm the shard is balancing. To confirm balancing activity, run db.stats() or db.printShardingStatus() in the test database. Example output of the db.stats() : use test db.stats() db.printShardingStatus() { "raw" : { "rs0/mongodb0.example.net:27017,mongodb1.example.net:27017,mongodb2.example.net:27017" : { "db" : "test", "collections" : 3, "objects" : 989316, "avgObjSize" : 111.99974123535857, "dataSize" : 110803136, "storageSize" : 174751744, "numExtents" : 14, "indexes" : 2, "indexSize" : 57370992, "fileSize" : 469762048, "nsSizeMB" : 16, "dataFileVersion" : { "major" : 4, "minor" : 5 }, "extentFreeList" : { "num" : 0, "totalSize" : 0 }, "ok" : 1 }, "rs1/mongodb3.example.net:27017,mongodb4.example.net:27017,mongodb5.example.net:27017" : { "db" : "test", "collections" : 3, "objects" : 14697, "avgObjSize" : 111.98258147921345, "dataSize" : 1645808, "storageSize" : 2809856, "numExtents" : 7, "indexes" : 2, "indexSize" : 1169168, "fileSize" : 67108864, "nsSizeMB" : 16, "dataFileVersion" : { 703 10.3. Sharded Cluster Tutorials