MongoDB 自动分片 auto sharding
MongoDB部署实验系列文章，MongoDB做为NoSQL数据库，最近几年持续升温，越来越多的企业都开始尝试用MongoDB代替原有Database做一些事情。MongoDB也在集群，分片，复制上也有相当不错的的表现。我通过将做各种MongoDB的部署实验进行介绍。
第三篇 MongoDB 自动分片 auto sharding，分为6个部分
1.初始化文件目录
2.启动shard节点
3.配置shard节点
4.插入数据分片实验
5.删除主分片
6.重置主分片
系统环境介绍：
Ubuntu 12.04. LTS 64bit Server
1. 初始化文件目录
创建目录
config1,config2,config3是配置节点
shard1,shard2,shard3是分片节点
~ pwd
/home/conan/dbs
~ mkdir config1 config2 config3 shard1 shard2 shard3
conan@u1:~/dbs$ ls -l
drwxrwxr-x 3 conan conan 4096 May 31 11:27 config1
drwxrwxr-x 3 conan conan 4096 May 31 11:27 config2
drwxrwxr-x 3 conan conan 4096 May 31 11:27 config3
drwxrwxr-x 3 conan conan 4096 May 31 11:28 shard1
drwxrwxr-x 3 conan conan 4096 May 31 11:29 shard2
drwxrwxr-x 3 conan conan 4096 May 31 11:29 shard3
2. 启动shard节点
启动config节点
~ mongod --dbpath /home/conan/dbs/config1 --port 20001 --nojournal --fork --logpath /home/conan/dbs/config1.log
~ mongod --dbpath /home/conan/dbs/config2 --port 20002 --nojournal --fork --logpath /home/conan/dbs/config2.log
~ mongod --dbpath /home/conan/dbs/config3 --port 20003 --nojournal --fork --logpath /home/conan/dbs/config3.log
启动mongos节点
~ mongos --configdb localhost:20001,localhost:20002,localhost:20003 --port 30001 --fork --logpath /home/conan/dbs/mongos1.log
~ mongos --configdb localhost:20001,localhost:20002,localhost:20003 --port 30002 --fork --logpath /home/conan/dbs/mongos2.log
启动shard节点
~ mongod --dbpath /home/conan/dbs/shard1 --port 10001 --nojournal --fork --logpath /home/conan/dbs/shard1.log
~ mongod --dbpath /home/conan/dbs/shard2 --port 10002 --nojournal --fork --logpath /home/conan/dbs/shard2.log
~ mongod --dbpath /home/conan/dbs/shard3 --port 10003 --nojournal --fork --logpath /home/conan/dbs/shard3.log
查看端口
~ netstat -nlt
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 0.0.0.0:21003 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:10001 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:30001 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:10002 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:30002 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:10003 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:11001 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:31001 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:11002 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:31002 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:11003 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:20001 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:20002 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:20003 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:21001 0.0.0.0:* LISTEN
tcp 0 0 0.0.0.0:21002 0.0.0.0:* LISTEN
tcp6 0 0 :::22 :::* LISTEN
3. 配置shard节点
连接mongos1，在mongos中添加分片：
~ mongo localhost:30001/admin
MongoDB shell version: 2.4.3
connecting to: localhost:30001/admin
mongos> db.runCommand({addshard : "localhost:10001", allowLocal : true})
{ "shardAdded" : "shard0000", "ok" : 1 }
mongos> db.runCommand({addshard : "localhost:10002", allowLocal : true})
{ "shardAdded" : "shard0001", "ok" : 1 }
mongos> db.runCommand({addshard : "localhost:10003", allowLocal : true})
{ "shardAdded" : "shard0002", "ok" : 1 }
错误的语法：(MongoDB2.0.4已经不支持此语法)
mongos> db.runCommand({addshard : "shard1/localhost:10001,localhost:10002",name:"s1", allowLocal : true})
{
"ok" : 0,
"errmsg" : "couldn't connect to new shard socket exception [CONNECT_ERROR] for shard1/localhost:10001,localhost:10002"
}
查看分片信息
mongos> db.runCommand({listshards:1})
{
"shards" : [
{
"_id" : "shard0000",
"host" : "localhost:10001"
},
{
"_id" : "shard0001",
"host" : "localhost:10002"
},
{
"_id" : "shard0002",
"host" : "localhost:10003"
}
],
"ok" : 1
}
启用数据库分片：fensme
mongos> db.runCommand({"enablesharding" : "fensme"})
{ "ok" : 1 }
注：一旦enable了个数据库，mongos将会把数据库里的不同数据集放在不同的分片上。只有数据集也被分片，否则一个数据集的所有数据将放在一个分片上。
启用数据集分片：fensme.users
mongos> db.runCommand({"shardcollection" : "fensme.users", "key" : {"_id" : 1,"uid":1}})
{ "collectionsharded" : "fensme.users", "ok" : 1 }
查看分片状态
mongos> db.printShardingStatus()
--- Sharding Status ---
sharding version: {
"_id" : 1,
"version" : 3,
"minCompatibleVersion" : 3,
"currentVersion" : 4,
"clusterId" : ObjectId("51a8d3287034310ad2f6a94e")
}
shards:
{ "_id" : "shard0000", "host" : "localhost:10001" }
{ "_id" : "shard0001", "host" : "localhost:10002" }
{ "_id" : "shard0002", "host" : "localhost:10003" }
databases:
{ "_id" : "admin", "partitioned" : false, "primary" : "config" }
{ "_id" : "fensme", "partitioned" : true, "primary" : "shard0000" }
fensme.users
shard key: { "_id" : 1, "uid" : 1 }
chunks:
shard0000 1
{ "_id" : { "$minKey" : 1 }, "uid" : { "$minKey" : 1 } } -->> { "_id" : { "$maxKey" : 1 }, "uid" : { "$maxKey" : 1 } } on : shard0000 { "t" : 1, "i" : 0 }
fensme数据库是支持shard的，主shard是shard0000，对应host是localhost:10001
MongoDB 的详细介绍：请点这里
MongoDB 的下载地址：请点这里
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