MongoDB master slave synchronization Settings For the installation and startup parameters of MongoDB, please refer to the “Ubuntu installation MongoDB” and “Mongodb startup command mongod parameters” I reprinted before.

Master-slave setup

Master :  192.168.111.103 Port : 8001
Slave : 192.168.111.104 Port : 8001

Start the Master

mongod --dbpath /data/masterdb/ --master --oplogSize 64 --port 8001 --fork --logpath /var/logs/mongodb/mongod.log

Start the Slave

mongod --dbpath /data/slavedb/ --slave --source 192.168.111.103:8001 --oplogSize 64 --port 8001 --fork --logpath /var/logs/mongodb/mongod.log

Looking at Slave log, you can see that the data has been copied from Master

tail -f /var/logs/mongodb/mongod.log
Thu Feb 27 22:18:20 repl: main@192.168.111.103:8001
Thu Feb 27 22:18:20 repl: sleep 2sec before next pass
Thu Feb 27 22:18:22 repl: main@192.168.111.103:8001
Thu Feb 27 22:18:22 repl: sleep 2sec before next pass
Thu Feb 27 22:18:24 repl: main@192.168.111.103:8001
Thu Feb 27 22:18:24 repl: sleep 2sec before next pass
Thu Feb 27 22:18:26 repl: main@192.168.111.103:8001
Thu Feb 27 22:18:26 repl: sleep 2sec before next pass
Thu Feb 27 22:18:28 repl: main@192.168.111.103:8001
Thu Feb 27 22:18:28 repl: sleep 2sec before next pass
Thu Feb 27 22:18:30 repl: main@192.168.111.103:8001
Thu Feb 27 22:18:30 repl: sleep 2sec before next pass
Thu Feb 27 22:18:32 repl: main@192.168.111.103:8001
Thu Feb 27 22:18:32 repl: sleep 2sec before next pass

Stop using MongoDB

mongo -port 8001
use admin
db.shutdownServer()
exit

Repair MongoDB

mongod --dbpath /data/masterdb/ repair
mongod --dbpath /data/slavedb/ repair

Mongodb launch command mongod parameter description

The main parameters of mongod are:

The basic configuration

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—quiet # quiet output —port arg # specifies the service port number, with the default port 27017 —bind_ip arg # binding service IP. If bound 127.0.0.1, it can only be accessed locally, and all IP are not specified by default —logpath arg # specifies the MongoDB log file. Note that the specified file is not a directory —logappend # logs with appends — the full path to pidfilepath arg # PID File, if not set, no PID file — the full path of the private key of the keyFile arg # cluster, only valid for the Replica Set architecture —unixSocketPrefix arg # UNIX domain socket substitution directory,(default /tmp) —fork # runs MongoDB as a daemon, creating a server process —auth # enables validation —cpu # shows CPU’s CPU utilization and iowait periodically —dbpath arg # specifies the database path —diaglog arg # diaglog option 0=off 1=W 2=R 3=both 7=W+some reads —directoryperdb # sets that each database will be saved in a separate directory — with the logging option enabled, the data operations of MongoDB will be written to files in the journal folder —journalOptions arg # enables log diagnostics —ipv6 # enables the IPv6 option —jsonp # allows the JSONP form to be accessed via HTTP (with security implications) — the maximum number of simultaneous connections maxConns arg # defaults to 2000 —noauth # does not enable validation —nohttpinterface # closes http interface, and port 27018 is closed by default —noprealloc # disables preallocation of data files (often affecting performance) —noscripting # disable the scripting engine —notablescan # does not allow table scans —nounixsocket # disables Unix socket listening —nssize arg (=16) # set the letter database.ns file size (MB) —objcheck # after receiving customer data, check the validity, —profile arg # file parameter 0=off 1=slow, 2=all —quota # limits the number of files per database and sets the default to 8 —quotaFiles arg # number of files allower per db, requires —quota —rest # opens simple rest API —repair # fixes all databases run repair on all dbs —repairpath arg # fixes the directory of files generated by the library, with the default directory name dbpath —slowms arg (=100) # value of slow for profile and console log —smallfiles # USES a smaller default file —syncdelay arg (=60) # number of seconds to write data to disk (0=never, not recommended) —sysinfo # prints 1 diagnostic system information —upgrade # if you need to upgrade the database * Replicaton parameter

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—fastsync # enables the slave library replication service from an dbpath database that is a snapshot of the master library and can be used to quickly enable synchronization —autoresync # if the slave library is much worse than the master, automatically resynchronize, —oplogSize arg # sets the size of oplog (MB) * as the master/slave parameter

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—master # main library mode —slave # slave mode —source arg # slave library port number —only arg # specifies the database replication for single 1 —slavedelay arg # sets the delay time for synchronizing the master from the library * Replica set(replica set) option:

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—replSet arg # sets the replica set name * Sharding(sharding) option

-------------------------------------------------------------------------------- —configsvr # declares that this is the config service for 1 cluster, default port 27019, default directory /data/configdb —shardsvr # declares that this is a sharding of 1 cluster, with the default port 27018 —noMoveParanoia # turns off bigotry for moveChunk data saving The above parameters can be written into the mongod.conf configuration document, for example:

dbpath = /data/mongodb
logpath = /data/mongodb/mongodb.log
logappend = true
port = 27017
fork = true
auth = true

e. g:

./mongod -shardsvr -replSet shard1 -port 16161 -dbpath /data/mongodb/data/shard1a -oplogSize 100 -logpath /data/mongodb/logs/shard1a.log -logappend -fork -rest