Mongodb 分片 手动维护chunk

mingche

--显示collection的chunk分布信息　　
db.collection.getShardDistribution()
　　

　　
显示chunk信息脚本：
　　
AllChunkInfo = function(ns, est){
　　
    var chunks = db.getSiblingDB("config").chunks.find({"ns" : ns}).sort({min:1}); //this will return all chunks for the ns ordered by min
　　
    //some counters for overall stats at the end
　　
    var totalChunks = 0;
　　
    var totalSize = 0;
　　
    var totalEmpty = 0;
　　
    print("ChunkID,Shard,ChunkSize,ObjectsInChunk"); // header row
　　
    // iterate over all the chunks, print out info for each
　　
    chunks.forEach(
　　
        function printChunkInfo(chunk) {
　　

　　
        var db1 = db.getSiblingDB(chunk.ns.split(".")[0]); // get the database we will be running the command against later
　　
        var key = db.getSiblingDB("config").collections.findOne({_id:chunk.ns}).key; // will need this for the dataSize call
　　
        // dataSize returns the info we need on the data, but using the estimate option to use counts is less intensive
　　
        var dataSizeResult = db1.runCommand({datasize:chunk.ns, keyPattern:key, min:chunk.min, max:chunk.max, estimate:est});
　　
        // printjson(dataSizeResult); // uncomment to see how long it takes to run and status
　　
        print(chunk._id+","+chunk.shard+","+dataSizeResult.size+","+dataSizeResult.numObjects);
　　
        totalSize += dataSizeResult.size;
　　
        totalChunks++;
　　
        if (dataSizeResult.size == 0) { totalEmpty++ }; //count empty chunks for summary
　　
        }
　　
    )
　　
    print("***********Summary Chunk Information***********");
　　
    print("Total Chunks: "+totalChunks);
　　
    print("Average Chunk Size (bytes): "+(totalSize/totalChunks));
　　
    print("Empty Chunks: "+totalEmpty);
　　
    print("Average Chunk Size (non-empty): "+(totalSize/(totalChunks-totalEmpty)));
　　
}
　　

　　

　　

　　
使用示例：
　　
mongos> AllChunkInfo("test1.users001", true);
　　
ChunkID,Shard,ChunkSize,ObjectsInChunk
　　
test1.users001-_id_MinKey,shard3,11347710,171935
　　
test1.users001-_id_-6148914691236517204,shard1,11293458,171113
　　
test1.users001-_id_-3074457345618258602,shard1,11320716,171526
　　
test1.users001-_id_0,shard3,11349096,171956
　　
test1.users001-_id_3074457345618258602,shard2,11340054,171819
　　
test1.users001-_id_6148914691236517204,shard2,11328966,171651
　　
***********Summary Chunk Information***********
　　
Total Chunks: 6
　　
Average Chunk Size (bytes): 11330000
　　
Empty Chunks: 0
　　
Average Chunk Size (non-empty): 11330000