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This section describes how to set up complete replication of a MySQL server. There are a number of different methods for setting up replication, and the exact method that you use will depend on how you are setting up replication, and whether you already have data within your master database.
There are some generic tasks which may be required for all replication setups:
You may want to create a separate user that will be used by your slaves to authenticate with the master to read the binary log for replication. The step is optional. See Section 16.1.1.1, “Creating a User for Replication”.
You must configure the master to support the binary log and configure a unique ID. See Section 16.1.1.2, “Setting the Replication Master Configuration”.
You must configure a unique ID for each slave that you want to connect to the master. See Section 16.1.1.3, “Setting the Replication Slave Configuration”.
Before starting a data snapshot or the replication process, you should record the position of the binary log on the master. You will need this information when configuring the slave so that the slave knows where within the binary log to start executing events. See Section 16.1.1.4, “Obtaining the Master Replication Information”.
If you already have data on your master and you want to synchronize your slave with this base data, then you will need to create a data snapshot of your database. You can create a snapshot using mysqldump (see Section 16.1.1.5, “Creating a Data Snapshot Using mysqldump”) or by copying the data files directly (see Section 16.1.1.6, “Creating a Data Snapshot Using Raw Data Files”).
You will need to configure the slave with the master settings, such as the host name, login credentials and binary log name and positions. See Section 16.1.1.10, “Setting the Master Configuration on the Slave”.
Once you have configured the basic options, you will need to follow the instructions for your replication setup. A number of alternatives are provided:
If you are establishing a new MySQL master and one or more slaves, then you need only set up the configuration, as you have no data to exchange. For guidance on setting up replication in this situation, see Section 16.1.1.7, “Setting Up Replication with New Master and Slaves”.
If you are already running a MySQL server, and therefore already have data that will need to be transferred to your slaves before replication starts, have not previously configured the binary log and are able to shut down your MySQL server for a short period during the process, see Section 16.1.1.8, “Setting Up Replication with Existing Data”.
If you are setting up additional slaves to an existing replication environment then you can set up the slaves without affecting the master. See Section 16.1.1.9, “Introducing Additional Slaves to an Existing Replication Environment”.
If you want to administer a MySQL replication setup, we suggest that you read this entire chapter through and try all statements mentioned in Section 12.6.1, “SQL Statements for Controlling Master Servers”, and Section 12.6.2, “SQL Statements for Controlling Slave Servers”. You should also familiarize yourself with the replication startup options described in Section 16.1.3, “Replication and Binary Logging Options and Variables”.
Note that certain steps within the setup process require the
SUPER
privilege. If you do not
have this privilege then enabling replication may not be
possible.
User Comments
If you are setting up replication through an SSH channel, be sure to specify "127.0.0.1" as the address of the database, not "localhost", as MySQL will use "localhost" as a trigger to use a pipe for the connection instead of TCP/IP, and thus will fail.
For Debian users : after copying all mysql data files from master to slave you can get the following error message :
---
/usr/bin/mysqladmin: connect to server at 'localhost' failed
error: 'Access denied for user 'debian-sys-maint'@'localhost' (using password: YES)'
---
* Which means that Mysql password for user 'debian-sys-maint' isn't the same as in file /etc/mysql/debian.cnf.
* Because this password is randomly generated, they are different for each installation, and we have to 'synchronize' this password between debian.cnf file and Mysql privileges.
1 - On the master, get a copy of the password string in /etc/mysql/debian.cnf
2 - On the slave, stop the Mysql server, edit /etc/mysql/debian.cnf and replace the password by the one of the master. Start the slave server.
If you want to change it
1 - Launch a Mysql client and select 'mysql' database
2 - run this : UPDATE `user` SET `Password` = password('[password]') where user='debian-sys-maint'
(the password seems to be encrypted but is not)
3 - stop the Mysql server (you get an error for 'debian-sys-maint')
4 - change and put same [password] in /etc/mysql/debian.cnf file
For people getting:
"ERROR 1218 (08S01): Error connecting to master: Lost connection to MySQL server during query"
Make sure that ,on you're master replication server, you change the following line in your my.cnf:
bind-address 127.0.0.1
to
#bind-address 127.0.0.1
Or change the address to your FQDN or ip-addres
It is possible to sync a database to a master while the master is in active use. Commands starting "M:" are run on the master, "S:" are run in the slave. Until the end, the slave state is undefined.
This works for InnoDB tables, if you have set transactionality to REPEATABLE-READ.
M: begin;
M: flush tables with read lock;
M: show master status;
M: show databases;
M: (for each db:)
M:__ show tables in $db;
M:__ (for each table:)
M:____ select 1 from $db.$table limit 1;
M: unlock tables;
M: set time_zone = '+00:00';
S: set foreign_key_checks = 0;
S: stop slave io_thread;
S: stop slave;
S: reset slave;
S: reset master;
S: set time_zone = '+00:00';
_: (for each database:)
S:__ show databases like '$db';
_:__ (if it does not exist:)
S:____ create database $db;
_:__ (for each table:)
M:____ show create table $db.$table;
S:____ show create table $db.$table;
_:____ (if different:)
S:______ drop table $db.$table;
_:____ (if different or not on slave:)
S:______ create table $db.$table .... ;
S:____ delete from $db.$table;
M:____ select * from $db.$table;
S:____ insert into $db.$table values ([...from above...]);
S:__ show tables in $db;
_:__ (for each table that shouldn't be there:)
S:____ drop table $db.$table;
S: show databases;
_: (for each db that shouldn't be there:)
S:__ drop database $db;
S: change master to [...details from show master above...];
S: start slave io_thread;
S: start slave;
M: rollback;
(Urghh... I see no way to embed code into these posts. Hence the ugly "____" thing to indicate indentation. I suggest copying into something with a non-proportinal font, to make it easier to read)
When setting up replication from a Windows installation and replicated to a Unix installation of 5.0.x; Remember that the database tables are Case Sensitive under the Unix variant (See 9.2.2. Identifier Case Sensitivity). So if your application does not take this into effect, sql commands work fine with the Windows copy, but break when ran against the backup/replicated server, or worse, the replication breaks due to the fact the Unix server can't find the table.
Be Safe, target your SQL for the Unix standard of "LowerCase" and you will be a happy developer/administrator!
These are the configuration i had try out:
MySQL Failover Circular Replication
===================================
Assume we have 2 servers: Server1 and Server2.
Server1 Settings
================
1. Put the option file my.cnf to Server1 path /etc with these settings:
[mysqld]
log-bin=mysql-bin
server-id = 1
auto_increment_increment = 10
auto_increment_offset = 1
2. Change mode/permission for my.cnf to _rw_r__r__ else mysql will igonore it.
sudo chmod 644 my.cnf
3. Stop and start mysql.
cd /Library/StartupItems/MySQLCOM
sudo ./MySQLCOM stop
sudo ./MySQLCOM start
4. Configure the server:
# create a user for replication process:
cd /usr/local/mysql/bin
./mysql -p -u root
create user replicant@'%' identified by 'password';
# Grant access rights:
GRANT SELECT, PROCESS, FILE, SUPER, REPLICATION CLIENT, REPLICATION SLAVE, RELOAD ON *.* TO replicant@'%';
Flush Privileges;
# Specify the info for the serve2:
CHANGE MASTER TO
MASTER_HOST='ip_of_server2',
MASTER_USER='replication_user_name_on_server2',
MASTER_PASSWORD='replication_password_on_server2';
# Start the listerner:
Start slave;
# Verify whether the replication is working:
show slave status\G
Server2 Settings
================
1. Put the option file my.cnf on to Server2 path /etc
with these settings:
[mysqld]
log-bin=mysql-bin
server-id = 2
auto_increment_increment = 10
auto_increment_offset = 2
2. Change mode/permission for my.cnf to _rw_r__r__ else mysql will igonore it.
sudo chmod 644 my.cnf
3. Stop and start mysql.
cd /Library/StartupItems/MySQLCOM
sudo ./MySQLCOM stop
sudo ./MySQLCOM start
4. Configure the server:
# create a user for replication process:
cd /usr/local/mysql/bin
./mysql -p -u root
create user replicant@'%' identified by 'password';
# Grant access rights:
GRANT SELECT, PROCESS, FILE, SUPER, REPLICATION CLIENT, REPLICATION SLAVE, RELOAD ON *.* TO replicant@'%';
Flush Privileges;
# Specify the info for the serve1:
CHANGE MASTER TO
MASTER_HOST='ip_of_server1',
MASTER_USER='replication_user_name_on_server1',
MASTER_PASSWORD='replication_password_on_server1';
# Example:
#
# CHANGE MASTER TO MASTER_HOST='125.564.12.1',
# MASTER_USER='replicant', MASTER_PASSWORD='password';
# Load data from Server1:
Load Data from Master;
# Start the listerner:
Start slave;
It is worth to mention that "SELECT ... FOR UPDATE" doesn't distribute the locks to all slaves, which creates room for "funny" results.
What will happen in a two-node solution with circular replication as described at http://www.onlamp.com/pub/a/onlamp/2006/04/20/advanced-mysql-replication.html is that the update is copied to the other node while the local update is overwritten.
This is a flaw that has to be considered, and the right way to resolve this is probably through the MySQL Cluster.
If you are using SSL and find that you can connect using the command line, yet get 'Access Denied' in the replication logs, check the permissions on your certificates! Mine turned out to be readable by root, but not by the mysql user that the replication runs as.
Here is a video tutorial for setting up replication that shows what happens in the event of the master server failing http://www.codefutures.com/mysql-replication-howto
Here's a step by step simple quick and dirty tutorial on how to setup replication in just 5 mysql command lines and editing of the /etc/mysql/my.cnf file on both the master and the slave.
Basically you just need to setup the server id, create a user with the right privilege and start the replication:
http://blog.bottomlessinc.com/2010/03/setting-up-mysql-replication/
The doc was confusing to me and not in chronological order.
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