Deploy a Primary Server with MariaDB Community Server 10.5¶

Configuration Files¶

MariaDB's packages include several bundled configuration files. It is also possible to create custom configuration files.

On RHEL, CentOS, and SLES, MariaDB's packages bundle the following configuration files:

• /etc/my.cnf

• /etc/my.cnf.d/client.cnf

• /etc/my.cnf.d/mysql-clients.cnf

• /etc/my.cnf.d/server.cnf

And on RHEL, CentOS, and SLES, custom configuration files from the following directories are read by default:

• /etc/my.cnf.d/

On Debian and Ubuntu, MariaDB's packages bundle the following configuration files:

• /etc/mysql/my.cnf

• /etc/mysql/mariadb.cnf

• /etc/mysql/mariadb.conf.d/50-client.cnf

• /etc/mysql/mariadb.conf.d/50-mysql-clients.cnf

• /etc/mysql/mariadb.conf.d/50-mysqld_safe.cnf

• /etc/mysql/mariadb.conf.d/50-server.cnf

• /etc/mysql/mariadb.conf.d/60-galera.cnf

And on Debian and Ubuntu, custom configuration files from the following directories are read by default:

• /etc/mysql/conf.d/

• /etc/mysql/mariadb.conf.d/

Configuring MariaDB¶

1. Determine which system variables and options you need to configure.

   Mandatory options and system variables for a Primary Server include:

   System Variable/Option	Description
   log_bin	Set this option to enable the Binary Log.
   server_id	Sets the numeric Server ID for this MariaDB Community Server. Must be unique in the deployment.

   Useful system variables and options for MariaDB Community Server include:

   System Variable/Option	Description
   datadir	Sets the path to the data directory. MariaDB Community Server writes data files to this directory, including tablespaces, logs, and schemas. Change it to use a non-standard location or to start the Server on a different data directory for testing.
   bind_address	Sets the local TCP/IP address on which MariaDB Community Server listens for incoming connections. Bind to 0.0.0.0 to make the Server accessible through any network interface.
   port	Sets the port MariaDB Community Server listens on. Use this system variable to use a non-standard port or when running multiple Servers on the same host for testing.
   max_connections	Sets the maximum number of simultaneous connections MariaDB Community Server allows.
   thread_handling	Sets how MariaDB Community Server handles threads for client connections.
   log_error	Sets the file name for the error log.
   innodb_buffer_pool_size	Sets the amount of memory InnoDB reserves for the Buffer Pool.
   innodb_log_file_size	Sets the size for each Redo Log file and innodb_log_files_in_group sets the number of Redo Log files used by InnoDB.
   innodb_io_capacity	Sets the maximum number of I/O operations per second that InnoDB can use.

   Useful system variables and options for a Primary Server include:

   System Variable/Option	Description
   binlog_format	Sets Binary Log events as row-based, statement-based, or a mix of rows and statements.
   gtid_domain_id	Sets the numeric domain identifier to use in Global Transaction ID's.
   gtid_strict_mode	Sets MariaDB Community Server to enforce global ordering for Global Transaction ID's.

2. Choose a configuration file in which to configure your system variables and options.

   It not recommended to make custom changes to one of the bundled configuration files. Instead, it is recommended to create a custom configuration file in one of the included directories. Configuration files in included directories are read in alphabetical order. If you want your custom configuration file to override the bundled configuration files, then it is a good idea to prefix the custom configuration file's name with a string that will be sorted last, such as z-.

   • On RHEL, CentOS, and SLES, a good custom configuration file would be: /etc/my.cnf.d/z-custom-my.cnf

   • On Debian and Ubuntu, a good custom configuration file would be: /etc/mysql/mariadb.conf.d/z-custom-my.cnf

3. Set your system variables and options in the configuration file.

   They need to be set in a group that will be read by mariadbd, such as [mariadb] or [server].

   For example:

   [mariadb]
   
   # Server Configuration
   log_error                 = mariadbd.err
   innodb_buffer_pool_size   = 1G
   
   # Replication Configuration (Primary Server)
   log_bin          = mariadb-bin
   server_id        = 1
   binlog_format    = ROW
   

Group Commit¶

Group commit can help performance by reducing I/O.

If you would like to configure parallel replication on the Replica, then it is also required to configure group commit on the Primary.

Semi-Synchronous Replication¶

MariaDB Replication deployments that use MariaDB Community Server 10.2 have the option of enabling semi-synchronous replication for Primary Servers through the semisync_master plugin.

Mandatory additional options and system variables for Semi-Synchronous Replication:

Useful system variables for Semi-Synchronous Replication:

Configure the Replication User¶

Replica Servers replicate from the Primary Server through client connections. In order for them to access the Primary Server, the Replica Servers require a user account with sufficient privileges.

1. Connect to the Primary Server using MariaDB Client using the root@localhost user account:

   $ sudo mariadb
   

2. Create the user account with the CREATE USER statement:

   CREATE USER repl@'%' IDENTIFIED BY 'repl_passwd';
   

3. Grant the user account the REPLICATION SLAVE privilege with the GRANT statement:

   GRANT REPLICATION SLAVE ON *.* TO repl@'%';
   

4. After you deploy the Replica Server, provide these account credentials to the CHANGE MASTER TO statement as the MASTER_USER and MASTER_PASSWORD options.