(function() { var s = new ShardingTest({name: "presplit", shards: 2, mongos: 1, other: {chunkSize: 1}}); s.adminCommand({enablesharding: "test"}); s.ensurePrimaryShard('test', 'shard0001'); // Insert enough data in 'test.foo' to fill several chunks, if it was sharded. bigString = ""; while (bigString.length < 10000) { bigString += "asdasdasdasdadasdasdasdasdasdasdasdasda"; } db = s.getDB("test"); inserted = 0; num = 0; var bulk = db.foo.initializeUnorderedBulkOp(); while (inserted < (20 * 1024 * 1024)) { bulk.insert({_id: num++, s: bigString}); inserted += bigString.length; } assert.writeOK(bulk.execute()); // Make sure that there's only one chunk holding all the data. s.printChunks(); primary = s.getPrimaryShard("test").getDB("test"); assert.eq(0, s.config.chunks.count(), "single chunk assertion"); assert.eq(num, primary.foo.count()); s.adminCommand({shardcollection: "test.foo", key: {_id: 1}}); // Make sure the collection's original chunk got split s.printChunks(); assert.lt(20, s.config.chunks.count(), "many chunks assertion"); assert.eq(num, primary.foo.count()); s.printChangeLog(); s.stop(); })();