mongos數據分佈不均勻，move chunk失敗

現象

2018-02-06T14:41:05.130+0800 I SHARDING [Balancer] moveChunk result: { cause: { ok: 0.0, errmsg: "can't accept new chunks because  there are still 1236 deletes from previous migration" }, ok: 0.0, errmsg: "moveChunk failed to engage TO-shard in the data transfer:  :: caused by :: UnknownError: can't accept new chunks because  there are still 1236 deletes...", code: 8 }

mongos集羣數據分佈不均勻，後臺日誌顯示move chunk失敗，我嘗試手工遷移，報錯一樣

mongos> sh.moveChunk("recruit.externalResumeStorage", {"rid" : "1836776472", "sourceId" : 6}, "udb-f4rrmx")

{
"cause" : {
"cause" : {
"ok" : 0,
"errmsg" : "can't accept new chunks because  there are still 1236 deletes from previous migration"
},
"ok" : 0,
"errmsg" : "moveChunk failed to engage TO-shard in the data transfer:  :: caused by :: UnknownError: can't accept new chunks because  there are still 1236 deletes from previous migration",
"code" : 8
},
"code" : 8,
"ok" : 0,
"errmsg" : "move failed"
}

故障原因

應該是bug，參考https://jira.mongodb.org/browse/SERVER-14047

解決方法

重啓整個mongos集羣，包括mongos節點，config節點，sharding節點