MongoDB replica set building and backup recovery

One, MongoDB replica set (REPL set) Introduction

Early version use Master-slave, a master one from and MySQL similar, but slave in this architecture is read-only, when the main library down, from the library can not automatically switch to primary;

Currently has eliminated the Master-slave mode, changed to a replica set, this mode has a master (primary), and multiple from (secondary), read-only, support to them set weights, when the main outage, the highest weight from the switch-based;

In this architecture, you can also establish a quorum (arbiter) role, which is only responsible for adjudication, not storing data

Read and write data in this architecture is the Lord, to achieve the purpose of load balancing needs to manually specify the target server to read the library

Second, MongoDB replica set construction

Server Environment Preparation

Three servers are CentOS release 6.5 (Final)

192.168.1.203 (primary)

192.168.1.201 (secondary)

192.168.1.202 (secondary)

Edit the configuration file for three machines and add the following:

Replication

Oplogsizemb:20 #oplog大小

Replsetname:fansik #名称自定义

Restart three MongoDB services

Connect the master, Run command MONGO in the Lord, and then

> Use admin

>config={_id: "Fanjinbao", Members:[{_id:0,host: "192.168.1.203:27017"},{_id:1,host: "192.168.1.201:27017"},{_ Id:2,host: "192.168.1.202:27017"}]}

> rs.initiate (config)

> Rs.add ("192.168.1.201")

> Rs.add ("192.168.1.202")

> Rs.status () # View status

If the two from the status of "Statestr": "STARTUP", you need to do the following > var config={_id: "Fanjinbao", Members:[{_id:0,host: " 192.168.1.203:27017 "},{_id:1,host:" 192.168.1.201:27017 "},{_id:2,host:" 192.168.1.202:27017 "}]}

> rs.initiate (config)

viewing Rs.status () again will find the state changed from secondary

Third, MongoDB copy set test

Our Lord built the library to build a collection

Use MyDB

Db.acc.insert ({accountid:1,username: "123", passwd: "123456"})

Show DBS

View from top

Show DBS if a series of errors occur

2016-05-13t00:03:36.719+0800 E QUERY error:listdatabases failed:{"note": "From ExecCommand", "OK": 0, "errmsg": "N OT Master "}

Perform

Rs.slaveok ()

Show DBS will see the database you created.

Iv. replica set Change weight simulation main outage

The default three machine weights are 1, if any one of the weights is set to higher than the other, then the machine immediately switch to primary role, so we preset three machines to the weight of 203:3,201:2,202:1

At the Lord's execution:

CFG = rs.conf ()

Cfg.members[0].priority = 3

Cfg.members[1].priority = 2

cfg.members[2].priority = 1

Rs.reconfig (CFG)

In this case, the second node will be a candidate node

The Lord discards packets entered from Port 27017

Iptables-i input-p TCP--dport 27017-j DROP

V. MongoDB Backup and Recovery

Back up the specified library

# mongodump-h ip-d dbname-o dir #-h back with server ip,-d back with database name, not add backup all libraries,-o specify where to back up, he is a directory

Back Up all libraries

# mongodump-h 192.168.1.203-o/tmp/

Backing up a specified collection

# mongodump-d fansik-c zhangsan-o/tmp/fansik #-c Specify the name of the collection

Export Collection as JSON file

# mongoexport-d mydb-c fansik-o/tmp/test.json #-o followed by the name of a file

Recover all libraries

# Mongorestore--drop dir/#其中dir是备份所有库的目录名字 which--drop optional, meaning to restore the data before deleting, not recommended to use

Restore the specified library

# mongorestore-d Mydb/mydb #-d Restored library name, MyDB is the library backup directory

Recovering collections

# mongorestore-d Mydb-c Zhangsan/fansik/zhangsan.bson #-c Back is the name of the collection to restore, then specify the recovered collection file, Bson format file

Import Collection

# mongoimport-d MYDB-C Test--file/tmp/test.json

MongoDB replica set building and backup recovery