MongoDB 集羣（二）

MongoDB 主從

主mongodb.config配置

• dbpath=/usr/data/mongodb/master/master/data/db
• logpath=/usr/data/mongodb/master/master/log/mongodb.log
• logappend=true
• fork=true
• bind_ip=192.168.1.1
• port=27001
• master=true
• source=192.168.1.1:27002

從mongodb.config配置

• dbpath=/usr/data/mongodb/master/slave/data/db
• logpath=/usr/data/mongodb/master/slave/log/mongodb.log
• logappend=true
• fork=true
• bind_ip=192.168.1.1
• port=27002
• slave=true
• source=192.168.1.1:27001

mongoDB官方已經不建議使用主從模式了，替代方案是採用副本集的模式

mongo --host 192.168.1.1 -port 27001

• > use test
• switched to db test
• > db.createCollection("my")
• { "ok" : 1 }
• > for(var i=0;i<100;i++)db.my.insert({name:"zhangsan"+i})
• WriteResult({ "nInserted" : 1 })
• > show collections
• my
• system.indexes
• > db.my.find();
• { "_id" : ObjectId("5833003a0c9c1401998c51ea"), "name" : "zhangsan0" }
• { "_id" : ObjectId("5833003a0c9c1401998c51eb"), "name" : "zhangsan1" }
• { "_id" : ObjectId("5833003a0c9c1401998c51ec"), "name" : "zhangsan2" }
• { "_id" : ObjectId("5833003a0c9c1401998c51ed"), "name" : "zhangsan3" }
• mongo --host 192.168.1.1 -port 27002
• > show dbs
• error: { "$err" : "not master and slaveOk=false", "code" : 13435 }

須要注意的是，從服務器默認狀況下是不支持讀寫的，可是會把數據同步到從服務器，不支持客戶端讀寫。須要客戶端鏈接從服務器時用命令支持讀：rs.slaveOk()

• > rs.slaveOk()
• > show dbs
• local  0.078GB
• test   0.078GB
• > use test
• switched to db test
• > show collections
• my
• system.indexes
• > db.my.find()
• { "_id" : ObjectId("5833003a0c9c1401998c51ea"), "name" : "zhangsan0" }
• { "_id" : ObjectId("5833003a0c9c1401998c51eb"), "name" : "zhangsan1" }
• { "_id" : ObjectId("5833003a0c9c1401998c51ec"), "name" : "zhangsan2" }