Mongodb Study Notes 08 and mongodb Study Notes

Mongodb Study Notes 08 and mongodb Study Notes

Official documentation:
Http://docs.mongodb.org/manual/replication/

Replication sets multiple servers maintain the same data copy

Step 1: how to use a replica set

When mongod is started, you must specify the replica set name. You can set the replica set name by adding-replSet name or setting replication. replSetName in the configuration file.

For example:

mongod --port 270217 --dbpath /mongo/database --logpath /mongo/log/mongo.log --replSet repl_test --smallfiles &mongod --port 270218 --dbpath /mongo2/database --logpath /mongo2/log/mongo.log --replSet repl_test --smallfiles &mongod --port 270219 --dbpath /mongo3/database --logpath /mongo3/log/mongo.log --replSet repl_test --smallfiles &

Step 2

Enter one of
For example:

mongo --port 27017

Then define the rs. initiate (rsconf) parameter rsconf

rsconf = {    _id:'repl_test',    members:    [        {            _id:0,host:'127.0.0.1:27017'                },        {            _id:1,host:'127.0.0.1:27018'                },        {            _id:2,host:'127.0.0.1:27019'                },    ]}

Step 3

Initialize a replica set

rs.initiate(rsconf)

Operation on replica set

View replica set information

Default Value: _ id: 0. mongod is the primary node.

rs.status() 

Delete a node

    rs.remove(host)

Add Node

rs.add(host)rs.reconfig(rsconf)

Operations can be performed on the master node by default. If you enter the secondary node, you need to run the CRUD operation.

rs.slaveOk()

If the master node goes down, one of the remaining nodes will automatically become the master node.

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