Template:OXLoadBalancingClustering Database
Master/Master database setup
This article describes the setup process "Master/Master replication" for new Open-Xchange database cluster. During configuration and initialization, other database operations must be prohibited.
The Master/Master replication is a vice versa setup of Master/Slave configurations. This means each server is afterwards the slave of the other.
Server IPs in the example are 1.1.1.1 and 9.9.9.9
Startup both database machines and install the mysql server packages
$ apt-get install mysql-server
During the installation, a dialog will show up to set a password for the MySQL 'root' user.
Open the MySQL configuration file on both servers:
$ vim /etc/mysql/my.cnf
Modify or enable the following configuration options in the mysqld-section, use 1 as ${unique Number} on the server 1.1.1.1 and 2 for 9.9.9.9:
bind-address = 0.0.0.0
server-id = ${unique Number}
log_bin = /var/log/mysql/mysql-bin.log
binlog_format = statement
- bindaddress specifies the network address where MySQL is listening for network connections. Since the MySQL slave and both Open-Xchange Servers are dedicated machines it is required to have the master accessible through the network.
- server-id is just a unique number within a environment with multiple MySQL servers. It needs to be unique for each server in a replication cluster.
- log-bin enables the MySQL binary log which is required for Master/Master replication. In general every statement triggered at the database is stored there to get distributed through the database cluster.
To apply the configuration changes, restart the MySQL servers.
$ /etc/init.d/mysql restart
Then login to MySQL with the credentials given at the MySQL installation process
$ mysql -u root -p Enter password:
First Master configuration
Choose one server to start with as the first Master (here we use 1.1.1.1).
Create a MySQL user with rights "REPLICATION". This account is used by the MySQL slave to fetch database updates. In this example, the username is "replication":
mysql> GRANT REPLICATION SLAVE ON *.* TO 'replication'@'9.9.9.9' IDENTIFIED BY 'secret';
Verify that the MySQL daemon writes a binary log and note the log Position and File name:
mysql> SHOW MASTER STATUS; +------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +------------------+----------+--------------+------------------+ | mysql-bin.000001 | 1111 | | | +------------------+----------+--------------+------------------+
First Slave configuration
On 9.9.9.9, set the MySQL system user as owner of the binary log that has just been copied to the slave.
$ chown mysql:adm /var/log/mysql/*
Configure MySQL on 9.9.9.9 to use 1.1.1.1 as Master Server. (Use the actual log File name and Position which you just obtained with the command SHOW MASTER STATUS on 1.1.1.1. as explained above.)
mysql> CHANGE MASTER TO MASTER_HOST='1.1.1.1', MASTER_USER='replication', MASTER_PASSWORD='secret', MASTER_LOG_FILE='mysql-bin.000001', MASTER_LOG_POS=1111;
Start the MySQL slave replication
mysql> START SLAVE;
And check the status
mysql> SHOW SLAVE STATUS\G;
"Slave_IO_Running" and "Slave_SQL_Running" should be set to "yes". Furthermore "Read_Master_Log_Pos" should be counting and "Seconds_Behind_Master" should be approaching the 0 mark.
Second Master configuration
This means, the first Master/Slave Replication is working and the "reverse" replication needs to be prepared. Please now create the replication user on 9.9.9.9:
mysql> GRANT REPLICATION SLAVE ON *.* TO 'replication'@'1.1.1.1' IDENTIFIED BY 'secret';
Verify that the MySQL daemon writes a binary log and remember the log Position:
mysql> SHOW MASTER STATUS; +------------------+----------+--------------+------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | +------------------+----------+--------------+------------------+ | mysql-bin.000009 | 9999| | | +------------------+----------+--------------+------------------+
Second Slave configuration
1.1.1.1 is now the slave in this context and 9.9.9.9 is the master. Log in to 1.1.1.1
Configure MySQL on 1.1.1.1 to use 9.9.9.9 as Master Server. Use the remembered log and file position from 1.1.1.1.
mysql> CHANGE MASTER TO MASTER_HOST='9.9.9.9', MASTER_USER='replication', MASTER_PASSWORD='secret', MASTER_LOG_FILE='mysql-bin.000009', MASTER_LOG_POS=9999;
start the MySQL slave replication
mysql> START SLAVE;
and check the status
mysql> SHOW SLAVE STATUS\G;
"Slave_IO_Running" and "Slave_SQL_Running" should be set to "yes". Furthermore "Read_Master_Log_Pos" should be counting and "Seconds_Behind_Master" should be approaching the 0 mark.
Also check the syslog if the replication has been sucessfully started
$ tail -fn20 /var/log/syslog Jul 26 19:03:45 dbslave mysqld[4718]: 090726 19:03:45 [Note] Slave I/O thread: connected to master 'replication@1.1.1.17:3306', replication started in log 'mysql-bin.000001' at position 10000
Testing Master/Master
On 1.1.1.1, create a new database in MySQL:
mysql> CREATE DATABASE foo;
Verify the database to als be available on 9.9.9.9 afterwards:
mysql> SHOW DATABASES; +--------------------+ | Database | +--------------------+ | information_schema | | foo | | mysql | +--------------------+
Delete the new database on 9.9.9.9:
mysql> DROP DATABASE foo;
Check if the database has also been removed on 1.1.1.1
mysql> SHOW DATABASES; +--------------------+ | Database | +--------------------+ | information_schema | | mysql | +--------------------+
Creating Open-Xchange user
Now setup access for the Open-Xchange Server database user 'openexchange' to configdb and the oxdb for both groupware server addresses. These databases do not exist yet, but will be created during the Open-Xchange Server installation.
Note: The IPs in this example belong to the two different Open-Xchange Servers, please adjust them accordingly.
mysql> GRANT ALL PRIVILEGES ON *.* TO 'openexchange'@'10.20.30.213' IDENTIFIED BY 'secret'; mysql> GRANT ALL PRIVILEGES ON *.* TO 'openexchange'@'10.20.30.215' IDENTIFIED BY 'secret';