mongos> sh.status()
--- Sharding Status --- 
  sharding version: {
	"_id" : 1,
	"minCompatibleVersion" : 5,
	"currentVersion" : 6,
	"clusterId" : ObjectId("582614b16369490a2de6a7dc")
}
  shards:
	{  "_id" : "shard0000",  "host" : "franklinia:20000",  "state" : 1 }
	{  "_id" : "shard0001",  "host" : "franklinia:20001",  "state" : 1 }
  active mongoses:
	"3.4.0-rc2-83-g54b9623" : 1
 autosplit:
	Currently enabled: no
  balancer:
	Currently enabled:  yes
	Currently running:  no
		Balancer lock taken at Fri Nov 11 2016 13:57:53 GMT-0500 (EST) by ConfigServer:Balancer
	Failed balancer rounds in last 5 attempts:  0
	Migration Results for the last 24 hours: 
		1 : Success
		1 : Failed with error 'aborted', from shard0001 to shard0001
  databases:
	{  "_id" : "test",  "primary" : "shard0000",  "partitioned" : true }
		test.foo
			shard key: { "_id" : 1 }
			unique: false
			balancing: true
			chunks:
				shard0000	1
				shard0001	1
			{ "_id" : { "$minKey" : 1 } } -->> { "_id" : 50000 } on : shard0001 Timestamp(2, 0) 
			{ "_id" : 50000 } -->> { "_id" : { "$maxKey" : 1 } } on : shard0000 Timestamp(2, 1) 

mongos> db.foo.findAndModify({query: {_id: {$gte: 23}}, sort: {_id: -1}, update: {$set: {z: "z"}}})
2016-11-11T14:09:57.261-0500 E QUERY    [main] Error: findAndModifyFailed failed: {
	"ok" : 0,
	"errmsg" : "query for sharded findAndModify must have shardkey",
	"code" : 61,
	"codeName" : "ShardKeyNotFound"
} :
_getErrorWithCode@src/mongo/shell/utils.js:25:13
DBCollection.prototype.findAndModify@src/mongo/shell/collection.js:768:1
@(shell):1:1
mongos> db.foo.findAndModify({query: {_id: {$eq: 23}}, sort: {_id: -1}, update: {$set: {z: "z"}}})
{
	"_id" : 23,
	"x" : "yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy",
	"y" : 0.8219226216897368
}