无论oracle还是mysql数据库都有分区的概念，即同一张表物理上不在同一台机器上，有效缓解了表都集中存在一台机器的压力。当然，mongodb也有类似的机制，即是分片。具体理论知识大家可以参考网上文档，我这里只记录下具体操作步骤
参考网络上一个图。我选用的是2个副本集+1个仲裁。实际上我这里分片集群需要3个mongos，3个config server，数据分片3个shard server，对应着还有3个副本，3个仲裁节点，总共需要15个实例。因为我资源确实紧张，又不想影响实验效果。冥思苦想了一阵，索性在一台机器上实现得了，分给不同的实例以不同的端口就好了。
闲话少说，开始搞起！！！
1. 资源划分（感觉这是最纠结的一步）
2. mongdb的安装
这个可以参考博主的前一篇章进行安装高可用mongodb集群的学习记录(一安装配置MongoDB)
3.创建所需要的目录
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#创建所需要的目录
[root@DB mongodb]
# mkdir -p mongos{1..3}/log
[root@DB mongodb]
# mkdir -p config{1..3}/log
[root@DB mongodb]
# mkdir -p config{1..3}/data
[root@DB mongodb]
# mkdir -p shard{1..3}_{1..3}/log
[root@DB mongodb]
# mkdir -p shard{1..3}_{1..3}/data
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4. 启动每一个配置服务器
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#启动配置服务器
mongod --configsvr --dbpath config1
/data
--port 21001 --logpath config1
/log/config
.log --fork
mongod --configsvr --dbpath config2
/data
--port 21002 --logpath config2
/log/config
.log --fork
mongod --configsvr --dbpath config3
/data
--port 21003 --logpath config3
/log/config
.log --fork
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5.启动mongos服务器
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mongos --configdb 192.168.221.160:21001,192.168.221.160:21002,192.168.221.160:21003 --port 20001 --logpath mongos1
/log/mongos
.log --fork
mongos --configdb 192.168.221.160:21001,192.168.221.160:21002,192.168.221.160:21003 --port 20002 --logpath mongos2
/log/mongos
.log --fork
mongos --configdb 192.168.221.160:21001,192.168.221.160:21002,192.168.221.160:21003 --port 20003 --logpath mongos3
/log/mongos
.log --fork
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6.启动分片的副本集
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mongod --shardsvr --replSet shard1 --port 21101 --dbpath shard1_1
/data
--logpath shard1_1
/log/shard
.log --fork --nojournal --oplogSize 10
mongod --shardsvr --replSet shard1 --port 21201 --dbpath shard1_2
/data
--logpath shard1_2
/log/shard
.log --fork --nojournal --oplogSize 10
mongod --shardsvr --replSet shard1 --port 21301 --dbpath shard1_3
/data
--logpath shard1_3
/log/shard
.log --fork --nojournal --oplogSize 10
mongod --shardsvr --replSet shard2 --port 21102 --dbpath shard2_1
/data
--logpath shard2_1
/log/shard
.log --fork --nojournal --oplogSize 10
mongod --shardsvr --replSet shard2 --port 21202 --dbpath shard2_2
/data
--logpath shard2_2
/log/shard
.log --fork --nojournal --oplogSize 10
mongod --shardsvr --replSet shard2 --port 21302 --dbpath shard2_3
/data
--logpath shard2_3
/log/shard
.log --fork --nojournal --oplogSize 10
mongod --shardsvr --replSet shard3 --port 21103 --dbpath shard3_1
/data
--logpath shard3_1
/log/shard
.log --fork --nojournal --oplogSize 10
mongod --shardsvr --replSet shard3 --port 21203 --dbpath shard3_2
/data
--logpath shard3_2
/log/shard
.log --fork --nojournal --oplogSize 10
mongod --shardsvr --replSet shard3 --port 21303 --dbpath shard3_3
/data
--logpath shard3_3
/log/shard
.log --fork --nojournal --oplogSize 10
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7.分别对每个分片配置副本集,任意登录一个节点
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#设置第一个分片副本集
[root@DB ~]
# mongo 192.168.221.160:21101
MongoDB shell version: 3.0.6
connecting to: 192.168.221.160:21101
/test
> use admin
switched to db admin
#定义副本集配置信息
> config = {_id:
"shard1"
,members:[{_id:0,host:
"192.168.221.160:21101"
},{_id:1,host:
"192.168.221.160:21201"
},{_id:2,host:
"192.168.221.160:21301"
,arbiterOnly:
true
}]}
{
"_id"
:
"shard1"
,
"members"
: [
{
"_id"
: 0,
"host"
:
"192.168.221.160:21101"
},
{
"_id"
: 1,
"host"
:
"192.168.221.160:21201"
},
{
"_id"
: 2,
"host"
:
"192.168.221.160:21301"
,
"arbiterOnly"
:
true
}
]
}
#初始化副本集信息
> rs.initiate(config)
{
"ok"
: 1 }
shard1:OTHER>
#设置第二个分片副本集
[root@DB ~]
# mongo 192.168.221.160:21102
MongoDB shell version: 3.0.6
connecting to: 192.168.221.160:21102
/test
> use admin
switched to db admin
> config = {_id:
"shard2"
,members:[{_id:0,host:
"192.168.221.160:21102"
},{_id:1,host:
"192.168.221.160:21202"
},{_id:2,host:
"192.168.221.160:21302"
,arbiterOnly:
true
}]}
{
"_id"
:
"shard2"
,
"members"
: [
{
"_id"
: 0,
"host"
:
"192.168.221.160:21102"
},
{
"_id"
: 1,
"host"
:
"192.168.221.160:21202"
},
{
"_id"
: 2,
"host"
:
"192.168.221.160:21302"
,
"arbiterOnly"
:
true
}
]
}
> rs.initiate(config)
{
"ok"
: 1 }
shard2:OTHER>
#设置第三个分片副本集
[root@DB ~]
# mongo 192.168.221.160:21103
MongoDB shell version: 3.0.6
connecting to: 192.168.221.160:21103
/test
> use admin
switched to db admin
> config = {_id:
"shard3"
,members:[{_id:0,host:
"192.168.221.160:21103"
},{_id:1,host:
"192.168.221.160:21203"
},{_id:2,host:
"192.168.221.160:21303"
,arbiterOnly:
true
}]}
{
"_id"
:
"shard3"
,
"members"
: [
{
"_id"
: 0,
"host"
:
"192.168.221.160:21103"
},
{
"_id"
: 1,
"host"
:
"192.168.221.160:21203"
},
{
"_id"
: 2,
"host"
:
"192.168.221.160:21303"
,
"arbiterOnly"
:
true
}
]
}
> rs.initiate(config)
{
"ok"
: 1 }
shard3:OTHER>
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8.登录到每一个mongos，设置分片配置，让分片生效
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#串联路由服务器与分片副本集1
[root@DB ~]
# mongo 192.168.221.160:20001
MongoDB shell version: 3.0.6
connecting to: 192.168.221.160:20001
/test
Server has startup warnings:
2017-11-15T13:51:20.732+0800 I CONTROL ** WARNING: You are running this process as the root user,
which
is not recommended.
2017-11-15T13:51:20.733+0800 I CONTROL
mongos> use admin
switched to db admin
mongos> db.runCommand({addshard:
"shard1/192.168.221.160:21101,192.168.221.160:21201,192.168.221.160:21301"
})
{
"shardAdded"
:
"shard1"
,
"ok"
: 1 }
mongos>
#串联路由服务器与分片副本集2
[root@DB ~]
# mongo 192.168.221.160:20002
MongoDB shell version: 3.0.6
connecting to: 192.168.221.160:20002
/test
Server has startup warnings:
2017-11-15T13:51:43.660+0800 I CONTROL ** WARNING: You are running this process as the root user,
which
is not recommended.
2017-11-15T13:51:43.661+0800 I CONTROL
mongos> use admin
switched to db admin
mongos> db.runCommand({addshard:
"shard2/192.168.221.160:21102,192.168.221.160:21202,192.168.221.160:21302"
})
{
"shardAdded"
:
"shard2"
,
"ok"
: 1 }
mongos>
#串联路由服务器与分片副本集3
[root@DB ~]
# mongo 192.168.221.160:20003
MongoDB shell version: 3.0.6
connecting to: 192.168.221.160:20003
/test
Server has startup warnings:
2017-11-15T13:51:59.589+0800 I CONTROL ** WARNING: You are running this process as the root user,
which
is not recommended.
2017-11-15T13:51:59.589+0800 I CONTROL
mongos> use admin
switched to db admin
mongos> db.runCommand({addshard:
"shard3/192.168.221.160:21103,192.168.221.160:21203,192.168.221.160:21303"
})
{
"shardAdded"
:
"shard3"
,
"ok"
: 1 }
mongos>
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9.查看分片服务器的配置信息：
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mongos> db.runCommand({listshards:1})
{
"shards"
: [
{
"_id"
:
"shard1"
,
"host"
:
"shard1/192.168.221.160:21101,192.168.221.160:21201"
},
{
"_id"
:
"shard2"
,
"host"
:
"shard2/192.168.221.160:21102,192.168.221.160:21202"
},
{
"_id"
:
"shard3"
,
"host"
:
"shard3/192.168.221.160:21103,192.168.221.160:21203"
}
],
"ok"
: 1
}
mongos>
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仲裁节点不储存数据，没有在这里显示出来
10.连接mongos上，指定数据库、指定集合让分片生效
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[root@DB ~]
# mongo 192.168.221.160:20001
MongoDB shell version: 3.0.6
connecting to: 192.168.221.160:20001
/test
mongos> db.runCommand({enablesharding:
"testdb"
})
{
"ok"
: 0,
"errmsg"
:
"enableSharding may only be run against the admin database."
,
"code"
: 13
}
mongos> use admin
switched to db admin
mongos> db.runCommand({enablesharding:
"testdb"
})
{
"ok"
: 1 }
mongos> db.runCommand({shardcollection:
"testdb.table1"
,key:{
id
:1}})
{
"collectionsharded"
:
"testdb.table1"
,
"ok"
: 1 }
mongos>
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设置testdb的 table1 表需要分片，根据 id 自动分片到 shard1 ，shard2，shard3 上面去。要这样设置是因为不是所有mongodb 的数据库和表都需要分片
11.测试分片片配置效果
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[root@DB ~]
# mongo 192.168.221.160:20001
MongoDB shell version: 3.0.6
connecting to: 192.168.221.160:20001
/test
Server has startup warnings:
2017-11-15T13:51:20.732+0800 I CONTROL ** WARNING: You are running this process as the root user,
which
is not recommended.
2017-11-15T13:51:20.733+0800 I CONTROL
mongos> use testdb;
switched to db testdb
mongos>
for
(var i = 1;i<=10000;i++) db.table1.save({
id
:i,
"test1"
:
"item1"
})
WriteResult({
"nInserted"
: 1 })
mongos> db.table1.stats()
{
"sharded"
:
true
,
"paddingFactorNote"
:
"paddingFactor is unused and unmaintained in 3.0. It remains hard coded to 1.0 for compatibility only."
,
"userFlags"
: 1,
"capped"
:
false
,
"ns"
:
"testdb.table1"
,
"count"
: 10000,
"numExtents"
: 7,
"size"
: 1120000,
"storageSize"
: 2809856,
"totalIndexSize"
: 654080,
"indexSizes"
: {
"_id_"
: 351568,
"id_1"
: 302512
},
"avgObjSize"
: 112,
"nindexes"
: 2,
"nchunks"
: 3,
"shards"
: {
"shard1"
: {
"ns"
:
"testdb.table1"
,
"count"
: 9991,
"size"
: 1118992,
...
"ok"
: 1,
"$gleStats"
: {
"lastOpTime"
: Timestamp(0, 0),
"electionId"
: ObjectId(
"5a0bd9cf86a6b76e11b5d820"
)
}
},
"shard2"
: {
"ns"
:
"testdb.table1"
,
"count"
: 1,
"size"
: 112,
...
"ok"
: 1,
"$gleStats"
: {
"lastOpTime"
: Timestamp(0, 0),
"electionId"
: ObjectId(
"5a0bdadd74c5945a33a4ae46"
)
}
},
"shard3"
: {
"ns"
:
"testdb.table1"
,
"count"
: 8,
"size"
: 896,
...
"ok"
: 1,
"$gleStats"
: {
"lastOpTime"
: Timestamp(0, 0),
"electionId"
: ObjectId(
"5a0bdb6f1c75115f41ff92f9"
)
}
}
},
"ok"
: 1
}
mongos>
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可以看到testdb.table1数据已经被分到三个分片，各自分片数量为 shard1 “count” : 9991，shard2 “count” : 1，shard3 “count” : 8。我也不知道为啥分配的不均匀。纳闷ing
好了，实验到此结束，关于mongodb的学习会继续进行...
本文转自 青苗飞扬 51CTO博客，原文链接:http://blog.51cto.com/qingmiao/1982044
