4台机器安装mongodb后，把4台机器的mongod启动，然后通过mongo连接你要做主机的mongo。

如以192.168.10.111:27017为主节点

master.conf配置

其他主机上mongo配置一样只需修改一下bindIP

#mongo 192.168.10.111:27017

然后修改mongodb配置

>use admin

>cfg={ _id:"rs01", members:[ {_id:0,host:'192.168.10.111:27017',priority:5}, {_id:1,host:'192.168.10.110:29017',priority:3},{_id:2,host:'192.168.10.112:27017',priority:2},{_id:3,host:'192.168.10.114:27017',arbiterOnly:true}] }

>rs.reconfig(cfg)

错误

> rs.reconfig(cfg)

{

"ok" : 0,

"errmsg" : "replSetReconfig should only be run on PRIMARY, but my state is REMOVED; use the \"force\" argument to override",

"code" : 10107

}

解决

> rs.reconfig(cfg,{"force":true})

错误

> rs.reconfig(cfg)

2016-04-23T15:41:01.557+0800 E QUERY    Error: Could not retrieve replica set config: {

"info" : "run rs.initiate(...) if not yet done for the set",

"ok" : 0,

"errmsg" : "no replset config has been received",

"code" : 94

}

at Function.rs.conf (src/mongo/shell/utils.js:1017:11)

at Function.rs.reconfig (src/mongo/shell/utils.js:969:22)

at (shell):1:4 at src/mongo/shell/utils.js:1017

解决

rs.initiate(cfg)

数值越大优先级越高，即priority值最大的为主节点

设置优先级

>use admin

>config=rs.conf()

>config.members[0].priority=5

>rs.reconfig(config,{force:true})

关闭mongod

#./mongo

>use admin

>db.shutdownServer()

启动mongodb脚本：
start_mongo_master.sh
#!/bin/sh
su mongodb -c "numactl --interleave=all /server/env/mongodb/bin/mongod --config /server/env/mongodb/mongod.conf --httpinterface --rest"

设置mongo打开文件数和打开程序书限制
/etc/pam.d/login文件中添加以下一行：
session    required     /lib64/security/pam_limits.so    //添加了这个，在limits.conf中添加限制用户资源马上生效

/etc/security/limits.conf文件添加以下限制
mongodb         soft    nofile          65535
mongodb         hard    nofile          65535
mongodb         soft    nproc           65536
mongodb         hard    nproc           65536

mongodb告警

解决：

把/dev/md0的readahead设置成256就行了

#blockdev --setra 256 /dev/md0

记得在rc.local中添加blockdev --setra 256 /dev/md0，要不然他每次都会恢复默认值

mongodb告警
** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.
 **        We suggest setting it to 'never'

** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is 'always'.
**        We suggest setting it to 'never'
解决：
/etc/rc.local中添加
echo "never" > /sys/kernel/mm/transparent_hugepage/enabled
echo "never" > /sys/kernel/mm/transparent_hugepage/defrag
这两行

自动备份数据库脚本

自动清理最近三天备份数据脚本

只有一个主机做mongo

#mongo --port 29017

>use admin

>cfg={_id:"rs1",members:[{_id:0,host:'192.168.0.212:29017',priority:1}]}

>rs.initiate(cfg)

现在mongo内存使用，mongodb3.2版本以上才有
storage:
    journal:
        enabled: true
        commitIntervalMs: 500
    directoryPerDB: true
    dbPath: "/server/env/mongodb-linux-x86_64-3.2.8/database"    
    engine: wiredTiger    
    wiredTiger:
        engineConfig:
            directoryForIndexes: true
            cacheSizeGB: 10
        collectionConfig:
            configString: "type=lsm"
        indexConfig:
            configString: "type=lsm"