shard0002 667
原本 shard0000 最大，shard0001 与 shard0002 为 0 。最终平均，数据将稳定不再变化。
mongos> db.kk.stats()
{
"sharded" : true,
"paddingFactorNote" : "paddingFactor is unused and unmaintained in 3.0. It remains hard coded to 1.0 for compatibility only.",
"userFlags" : 1,
"capped" : false,
"ns" : "test.kk",
"count" : 99999,
"numExtents" : 19,
"size" : 11199888,
"storageSize" : 44871680,
"totalIndexSize" : 10416224,
"indexSizes" : {
"_id_" : 4750256,
"id_hashed" : 5665968
},
"avgObjSize" : 112,
"nindexes" : 2,
"nchunks" : 2001,
"shards" : {
"shard0000" : {
"ns" : "test.kk",
"count" : 33500,
"size" : 3752000,
"avgObjSize" : 112,
"numExtents" : 7,
"storageSize" : 22507520,
"lastExtentSize" : 11325440,
"paddingFactor" : 1,
"paddingFactorNote" : "paddingFactor is unused and unmaintained in 3.0. It remains hard coded to 1.0 for compatibility only.",
"userFlags" : 1,
"capped" : false,
"nindexes" : 2,
"totalIndexSize" : 3605616,
"indexSizes" : {
"_id_" : 1913184,
"id_hashed" : 1692432
},
"ok" : 1
},
"shard0001" : {
"ns" : "test.kk",
"count" : 32852,
"size" : 3679424,
"avgObjSize" : 112,
"numExtents" : 6,
"storageSize" : 11182080,
"lastExtentSize" : 8388608,
"paddingFactor" : 1,
"paddingFactorNote" : "paddingFactor is unused and unmaintained in 3.0. It remains hard coded to 1.0 for compatibility only.",
"userFlags" : 1,
"capped" : false,
"nindexes" : 2,
"totalIndexSize" : 3343984,
"indexSizes" : {
"_id_" : 1389920,
"id_hashed" : 1954064
},
"ok" : 1
},
"shard0002" : {
"ns" : "test.kk",
"count" : 33647,
"size" : 3768464,
"avgObjSize" : 112,
"numExtents" : 6,
"storageSize" : 11182080,
"lastExtentSize" : 8388608,
"paddingFactor" : 1,
"paddingFactorNote" : "paddingFactor is unused and unmaintained in 3.0. It remains hard coded to 1.0 for compatibility only.",
"userFlags" : 1,
"capped" : false,
"nindexes" : 2,
"totalIndexSize" : 3466624,
"indexSizes" : {
"_id_" : 1447152,
"id_hashed" : 2019472
},
"ok" : 1
}
},
"ok" : 1
}
mongos>
上面中，个分片数据分布情况：
"shard0000" "count" : 33500
"shard0001" "count" : 32852
"shard0002" "count" : 33647
总计99999 行，完全准确，数据分布也很平均了。
（测试数据尽量多些，否则看不得效果。一开始本人测试数据较少，不到1000行，没有效果，还以为哪里出现问题，又多折腾了2小时！~）