That's normal - multiple mongos processes try to acquire a balancing lock but only one at a time can hold it. The balancing is done one chunk at a time so give it a bit of time to balance things completely. Google グループ 別にこれ出てるか…

なんかワンライナーって言いたくないｗ % cat foo 2016/01/01, 10 2016/01/01, 30 2016/01/01, 20 2016/01/03, 30 2016/01/05, 30 2016/01/10, 40 2016/01/13, 10 2016/01/13, 10 2016/01/13, 10 2016/01/23, 50 2016/01/23, 10 2016/01/25, 20 2016/01/26, …