MongoDB支持两种复制模式：
- 主从复制(Master/Slave)
- 复制集复制(Replica Set)
下面主要记录我在centos虚拟机上安装replica set，主要参考：http://docs.mongodb.org/manual/tutorial/deploy-replica-set/
首先准备好3份配置文件：
1
port = 27017
2
3
dbpath = /home/bells/install/
data1
4
logpath = /home/bells/install/log1/1
.log
5
6
fork =
true
7
replSet = rs0
1
port = 27016
2
3
dbpath = /home/bells/install/
data2
4
logpath = /home/bells/install/log2/2
.log
5
6
fork =
true
7
replSet = rs0
1
port = 27015
2
3
dbpath = /home/bells/install/
data3
4
logpath = /home/bells/install/log3/3
.log
5
6
fork =
true
7
replSet = rs0
然后再启动这3个mongodb服务
sudo ./mongodb1/bin/mongod --smallfiles --config 1
.conf
sudo .
/mongodb2/bin/mongod --smallfiles --config 2
.conf
sudo .
/mongodb3/bin/mongod --smallfiles --config 3.conf
其实smallfiles也应该写进*.conf文件中的。
最后配置：
主要是通过下面的命令
rs.initiate() 使用默认的配置初始化replica set在当前的服务器
rs.status() 显示当前replica set的状态
rs.add(serverInfo) 增加新的成员到replica set 中
rs.addArb(serverInfo) 增加一个arbiter到replica set中
1
rs.initiate()
2
{
3
"info2" : "no configuration explicitly specified -- making one"
,
4
"me" : "localhost.localdomain:27017"
,
5
"info" : "Config now saved locally. Should come online in about a minute."
,
6
"ok" : 1
7
}
8
>
rs.conf()
9
{
10
"_id" : "rs0"
,
11
"version" : 1
,
12
"members"
: [
13
{
14
"_id" : 0
,
15
"host" : "localhost.localdomain:27017"
16
}
17
]
18
}
19
rs0:PRIMARY> rs.add("localhost.localdomain:27016"
)
20
{ "ok" : 1
}
21
rs0:PRIMARY> rs.add("localhost.localdomain:27015"
)
22
{ "ok" : 1
}
23
rs0:PRIMARY>
rs.status()
24
{
25
"set" : "rs0"
,
26
"date" : ISODate("2014-02-23T01:43:16Z"
),
27
"myState" : 1
,
28
"members"
: [
29
{
30
"_id" : 0
,
31
"name" : "localhost.localdomain:27017"
,
32
"health" : 1
,
33
"state" : 1
,
34
"stateStr" : "PRIMARY"
,
35
"uptime" : 602
,
36
"optime" : Timestamp(1393119782, 1
),
37
"optimeDate" : ISODate("2014-02-23T01:43:02Z"
),
38
"self" :
true
39
},
40
{
41
"_id" : 1
,
42
"name" : "localhost.localdomain:27016"
,
43
"health" : 1
,
44
"state" : 5
,
45
"stateStr" : "STARTUP2"
,
46
"uptime" : 17
,
47
"optime" : Timestamp(0, 0
),
48
"optimeDate" : ISODate("1970-01-01T00:00:00Z"
),
49
"lastHeartbeat" : ISODate("2014-02-23T01:43:15Z"
),
50
"lastHeartbeatRecv" : ISODate("2014-02-23T01:43:15Z"
),
51
"pingMs" : 0
,
52
"lastHeartbeatMessage" : "initial sync need a member to be primary or secondary to do our initial sync"
53
},
54
{
55
"_id" : 2
,
56
"name" : "localhost.localdomain:27015"
,
57
"health" : 1
,
58
"state" : 5
,
59
"stateStr" : "STARTUP2"
,
60
"uptime" : 14
,
61
"optime" : Timestamp(0, 0
),
62
"optimeDate" : ISODate("1970-01-01T00:00:00Z"
),
63
"lastHeartbeat" : ISODate("2014-02-23T01:43:16Z"
),
64
"lastHeartbeatRecv" : ISODate("2014-02-23T01:43:16Z"
),
65
"pingMs" : 1
,
66
"lastHeartbeatMessage" : "syncThread: 12520 new file allocation failure"
67
}
68
],
69
"ok" : 1
70
}
71
rs0:PRIMARY> db.person.insert({"name":"jack", "age":20
})
72
rs0:PRIMARY>
db.person.find()
73
{ "_id" : ObjectId("5309529869d3a7216c59ef2a"), "name" : "jack", "age" : 20 }
1
[bells@localhost install]$ ./mongodb2/bin/mongo --port 27016
2
MongoDB shell version: 2.4.5
3
connecting to: 127.0.0.1:27016/
test
4
rs0:SECONDARY>
db.person.find()
5
error: { "$err" : "not master and slaveOk=false", "code" : 13435
}
6
rs0:SECONDARY>
rs.slaveOk();
7
rs0:SECONDARY>
db.person.find()
8
{ "_id" : ObjectId("5309529869d3a7216c59ef2a"), "name" : "jack", "age" : 20 }
安装部署过程中，遇到两个问题：
1. 启动mongodb时，错误日志：
1
Sun Feb 23 09:47:57.930 [initandlisten] ERROR: Insufficient free space
for
journal files
2
Sun Feb 23 09:47:57.930 [initandlisten] Please make at least 3379MB available in /home/bells/install/data1/journal or use --
smallfiles
3
Sun Feb 23 09:47:57.930
[initandlisten]
4
Sun Feb 23 09:47:57.953 [initandlisten] exception in initAndListen: 15926 Insufficient free space
for
journals, terminating
解决办法就是，启动的时候，加个 --smallfiles ： 这个参数默认值是false，如果设为true，则会是每个文件最大的大小限定为512M而不是默认的2G
2. 在secondary中，查询时：
1
rs0:SECONDARY>
db.person.find()
2
error: { "$err" : "not master and slaveOk=false", "code" : 13435 }
这个是正常的，因为SECONDARY默认是不允许读写操作的，可以：
rs0:SECONDARY> db.slaveOk();
来解决！
