[TOC] > [參考](https://blog.51cto.com/john88wang/1619817) ## 1. 確保Blancer進程已經開啟 ``` mongos> sh.getBalancerState() true // 開啟 mongos > sh.startBalancer(); /*{ "ok" : 1 }*/ //停止 mongos > sh.stopBalancer(); /*{ "ok" : 1 }*/ ``` ## 2.移走你要的分片 ``` mongos> sh.status(); mongos> use admin; //移走分片上的數據塊 mongos> db.runCommand({removeShard : "shard3"}) // 查看遷移狀態 mongos> db.runCommand({removeShard : "shard3"}) /* { "msg" : "draining ongoing", "state" : "ongoing", "remaining" : { "chunks" : NumberLong(0), //降為0 "dbs" : NumberLong(2) }, "note" : "you need to drop or movePrimary these databases", "dbsToMove" : [ "taiwan_game4", "taiwan_game5" ], "ok" : 1 } */ ``` ## 如果一個分片是一個或者多個數據庫的primary shard ``` mongos> use admin; mongos> db.runCommand( { movePrimary: "taiwan_game4", to: "taiwan_shard2" }) mongos> db.runCommand( { movePrimary: "taiwan_game5", to: "taiwan_shard2" }) ``` ## 結束遷移過程 ``` mongos> db.runCommand({removeShard : "taiwan_shard1"}) { "msg" : "removeshard completed successfully", "state" : "completed", "shard" : "taiwan_shard1", "ok" : 1 } ``` 當state狀態為completed時，遷移完成。