MongoDB整理笔记の新增Shard Server

    1、启动一个新Shard Server 进程

[root@localhost ~]# mkdir /data/shard/s2
[root@localhost ~]# /Apps/mongo/bin/mongod --shardsvr --port 20002 --dbpath /data/shard/s2
--fork --logpath /data/shard/log/s2.log --directoryperdb
all output going to: /data/shard/log/s2.log
forked process: 6772

    2、配置新Shard Server

[root@localhost ~]# /Apps/mongo/bin/mongo admin --port 40000
MongoDB shell version: 1.8.1
connecting to: 127.0.0.1:40000/admin
> db.runCommand({ addshard:"localhost:20002" })
{ "shardAdded" : "shard0002", "ok" : 1 }
> printShardingStatus()
--- Sharding Status ---
sharding version: { "_id" : 1, "version" : 3 }
shards:
{ "_id" : "shard0000", "host" : "localhost:20000" }
{ "_id" : "shard0001", "host" : "localhost:20001" }
{ "_id" : "shard0002", "host" : "localhost:20002" } --新增Shard Server
databases:
{ "_id" : "admin", "partitioned" : false, "primary" : "config" }
{ "_id" : "test", "partitioned" : true, "primary" : "shard0000" }
test.users chunks:
shard0002 2
shard0000 21
shard0001 21
too many chunksn to print, use verbose if you want to force print
test.users_2 chunks:
shard0001 46
shard0002 1
shard0000 45
too many chunksn to print, use verbose if you want to force print

   3、 查看分片表状态，以验证新Shard Server

> use test
switched to db test
> db.users_2.stats()
{
"sharded" : true,
"ns" : "test.users_2",
……
"shard0002" : { --新的Shard Server 已有数据
"ns" : "test.users_2",
"count" : 21848,
"size" : 2097408,
"avgObjSize" : 96,
"storageSize" : 2793472,
"numExtents" : 5,
"nindexes" : 1,
"lastExtentSize" : 2097152,
"paddingFactor" : 1,
"flags" : 1,
"totalIndexSize" : 1277952,
"indexSizes" : {
"_id_" : 1277952
},
"ok" : 1
}
},
"ok" : 1
}
>

    我们可以发现，当我们新增Shard Server 后数据自动分布到了新Shard 上，这是由MongoDB内部自已实现的。