Chunk Collection Aggregations

gistfile1.js

mongos> chunksPerShard_Aggregation
{ "$group" : { "_id" : "$shard", "count" : { "$sum" : 1 } } }
mongos> chunksPerShardByNS_Aggregation
{
	"$group" : {
		"_id" : {
			"shard" : "$shard",
			"ns" : "$ns"
		},
		"count" : {
			"$sum" : 1
		}
	}
}
mongos> db.chunks.aggregate(chunksPerShard_Aggregation);
{
	"result" : [
		{
			"_id" : "d42f619034d73616dabde1ed098739c2",
			"count" : 56
		},
		{
			"_id" : "4fa0d97504185879b6e7524dda47d98b",
			"count" : 56
		},
		{
			"_id" : "d34ff18d819ea9dfeda0f638eae589f0",
			"count" : 57
		},
		{
			"_id" : "af6e8730844faa627625a6c3fa98f0fc",
			"count" : 56
		},
		{
			"_id" : "0e5302a229a01e20cf4e29ae4f352c54",
			"count" : 4026
		}
	],
	"ok" : 1
}
mongos> db.chunks.aggregate(chunksPerShardByNS_Aggregation);
{
	"result" : [
		{
			"_id" : {
				"shard" : "d42f619034d73616dabde1ed098739c2",
				"ns" : "ChunkHunterTest.ChunkHunter"
			},
			"count" : 56
		},
		{
			"_id" : {
				"shard" : "d34ff18d819ea9dfeda0f638eae589f0",
				"ns" : "ChunkHunterTest.ChunkHunter"
			},
			"count" : 57
		},
		{
			"_id" : {
				"shard" : "4fa0d97504185879b6e7524dda47d98b",
				"ns" : "ChunkHunterTest.ChunkHunter"
			},
			"count" : 56
		},
		{
			"_id" : {
				"shard" : "0e5302a229a01e20cf4e29ae4f352c54",
				"ns" : "chunktest.prefixsplit"
			},
			"count" : 3969
		},
		{
			"_id" : {
				"shard" : "af6e8730844faa627625a6c3fa98f0fc",
				"ns" : "ChunkHunterTest.ChunkHunter"
			},
			"count" : 56
		},
		{
			"_id" : {
				"shard" : "0e5302a229a01e20cf4e29ae4f352c54",
				"ns" : "ChunkHunterTest.ChunkHunter"
			},
			"count" : 57
		}
	],
	"ok" : 1
}
mongos>