Excellent MongoDB learning materials 8. Replication (2)

2. MasterSlaveMasterSlave is a typical backup solution. MongoDB supports multiple deployment methods, such as OneMasterMultiSalver and MultiMasterOneSlave. Start with a simple backup of the image. $ Sudomkdir-pvarmongodb0 $ sudomkdir-pvarmongodb1 $ sudo. mongod --

2. Master/Slave is a typical backup solution. MongoDB supports One Master Multi Salver and Multi Master One Slave among other deployment modes. Start with a simple backup of the image. $ Sudo mkdir-p/var/mongodb/0 $ sudo mkdir-p/var/mongodb/1 $ sudo./mongod --

2. Master/Slave

Master/Slave is a typical backup solution. MongoDB supports multiple deployment methods, such as "One Master Multi Salver" and "Multi Master One Slave.

Start with a simple "backup image.

$ sudo mkdir -p /var/mongodb/0$ sudo mkdir -p /var/mongodb/1$ sudo ./mongod --fork --logpath /dev/null --dbpath /var/mongodb/0 --masterforked process: 1388all output going to: /dev/null$ sudo ./mongod --fork --logpath /dev/null --dbpath /var/mongodb/1 --port 27018 --slave --source localhost:27017 --autoresyncforked process: 1401all output going to: /dev/null

The autoresync parameter automatically starts the replication operation when the Master/Slave Data is in different steps due to system exceptions (synchronous replication is performed only once within 10 minutes ). In addition, you can use -- slavedelay to set the update frequency (in seconds ).

Use commands such as isMaster, printReplicationInfo, and printSlaveReplicationInfo to obtain relevant status information.

$ ./mongo > db.isMaster(){ "ismaster" : true, "ok" : 1 }> db.printReplicationInfo()configured oplog size:   990MBlog length start to end: 1164secs (0.32hrs)oplog first event time:  Mon Aug 23 2010 12:23:54 GMT+0800 (CST)oplog last event time:   Mon Aug 23 2010 12:43:18 GMT+0800 (CST)now:                     Mon Aug 23 2010 12:43:24 GMT+0800 (CST)$ ./mongo localhost:27018> db.isMaster(){ "ismaster" : false, "ok" : 1 }> db.printSlaveReplicationInfo()source:   localhost:27017         syncedTo: Mon Aug 23 2010 12:43:58 GMT+0800 (CST)                 = 10secs ago (0hrs)> show dbsadminlocaltest> use localswitched to db local> show collectionsmepair.syncsourcessystem.indexes> db.sources.find(){ "_id" : ObjectId("4c71f8178d806ad3f54dd89a"), "host" : "localhost:27017", "source" : "main", "syncedTo" : { "t" : 1282538738000, "i" : 1 }, "localLogTs" : { "t" : 0, "i" : 0 } }

The Slave configuration information is saved in local. sources.

We usually use the Master/Slave scheme for read/write splitting, but we need to set Slave_ OK.

$ IpythonIPython 0.10 -- An enhanced Interactive Python. in [1]: from pymongo import * In [2]: m_conn = Connection () In [3]: s_conn = Connection (host = "localhost: 27018", slave_okay = True) in [4]: m_db = m_conn.testIn [5]: s_db = s_conn.test # metadata # In [6]: m_db.users.insert ({"name": "user3"}) Out [6]: objectId ('4c71feb0499b140632000000 ') In [7]: s_db.users.find_one ({"name": "user3"}) # data is copied to SlaveOut [7]: {u' _ id ': objectId ('4c71feb0499b140632000000 '), u 'name': u 'user3'} In [8]: m_db.users.remove ({"name": "user3 "}) # Delete Master data In [9]: for u in m_db.users.find (): print u ....: {U' _ id': ObjectId ('4c71fa4d5e01e1ba6d62398f'), u 'name': u'user1'} In [10]: for u in s_db.users.find (): print u # The Slave record is deleted synchronously ....: {U' _ id': ObjectId ('4c71fa4d5e01e1ba6d62398f'), u 'name': u'user1'} # region # In [11]: s_db.users.insert ({"name ": "userx"}) # insert data Out of Slave [11]: ObjectId ('4c71ff2c499b140632000001 ') In [12]: for u in m_db.users.find (): print u # This data does not exist on the Master ....: {U' _ id': ObjectId ('4c71fa4d5e01e1ba6d62398f'), u 'name': u'user1'} In [13]: for u in s_db.users.find (): print u # Slave also does not have ....: {U' _ id': ObjectId ('4c71fa4d5e01e1ba6d62398f'), u 'name': u'user1 '}

It can be seen that the Slave read operation is normal, but the write operation is ineffective.

We can also deploy the "One Slave Two Master" solution.

$ sudo mkdir -p /var/mongodb/m1$ sudo mkdir -p /var/mongodb/m2$ sudo mkdir -p /var/mongodb/s$ sudo ./mongod --fork --dbpath /var/mongodb/m1 --logpath /dev/null --masterforked process: 1616all output going to: /dev/null$ sudo ./mongod --fork --dbpath /var/mongodb/m2 --logpath /dev/null --port 27018 --masterforked process: 1627all output going to: /dev/null$ sudo ./mongod --fork --dbpath /var/mongodb/s --logpath /dev/null --port 27019 --slaveforked process: 1638all output going to: /dev/null

Connect to Slave and add configurations.

$ ./mongo localhost:27019MongoDB shell version: 1.6.1connecting to: localhost:27019/test> use localswitched to db local> db.sources.insert({host:"localhost:27017"})> db.sources.insert({host:"localhost:27018"})> db.printSlaveReplicationInfo()source:   localhost:27017         syncedTo: Mon Aug 23 2010 13:06:03 GMT+0800 (CST)                 = 17secs ago (0hrs)source:   localhost:27018         doing initial sync

Add data to the two masters to view the replication effect.

$ ./mongo localhost:27017MongoDB shell version: 1.6.1connecting to: localhost:27017/test> use db1switched to db db1> db.users.insert({name:"user1"})> db.users.insert({name:"user2"})> db.users.find(){ "_id" : ObjectId("4c720211ade34e85c5380eab"), "name" : "user1" }{ "_id" : ObjectId("4c720214ade34e85c5380eac"), "name" : "user2" }> exitbye

$ ./mongo localhost:27018MongoDB shell version: 1.6.1connecting to: localhost:27018/test> use db2switched to db db2> db.blogs.insert({title:"aaa"})> db.blogs.insert({title:"bbb"})> db.blogs.insert({title:"ccc"})> db.blogs.find(){ "_id" : ObjectId("4c720236f24118cb2f59218d"), "title" : "aaa" }{ "_id" : ObjectId("4c720239f24118cb2f59218e"), "title" : "bbb" }{ "_id" : ObjectId("4c72023cf24118cb2f59218f"), "title" : "ccc" }> exitbye

$ ./mongo localhost:27019MongoDB shell version: 1.6.1connecting to: localhost:27019/test> show dbsadmindb1db2local> use db1switched to db db1> db.users.find(){ "_id" : ObjectId("4c720211ade34e85c5380eab"), "name" : "user1" }{ "_id" : ObjectId("4c720214ade34e85c5380eac"), "name" : "user2" }> use db2switched to db db2> db.blogs.find(){ "_id" : ObjectId("4c720236f24118cb2f59218d"), "title" : "aaa" }{ "_id" : ObjectId("4c720239f24118cb2f59218e"), "title" : "bbb" }{ "_id" : ObjectId("4c72023cf24118cb2f59218f"), "title" : "ccc" }>

Everything works.