Following are some configuration considerations if you have multiple MySQL database servers and databases:
- If running active/active or muliple MySQL instances (of the same or different versions), please consider using the mysqld Group feature if possible. SIOS recommends using mysqld Groups (mysqld_multi) for multiple MySQL database server configurations.
- If running active/active or multiple instances of MySQL, do not mount a shared file system as /var/lib/mysql. This causes unexpected shutdown of MySQL servers by the mysql startup command (safe_mysqld or mysqld_safe).
- The my.cnf file must be stored in the data directory for each of the active/active or multiple servers if not using the mysqld group feature. For configurations using mysqld Groups, the my.cnf file should be stored in /etc and not in the data directory. For more information on LifeKeeper and the mysqld Group feature, see Using mysqld Groups with LifeKeeper.
- Additional port numbers for MySQL must be specified in the /etc/services file.
- Each MySQL database server must be configured to run on a different port and access a different socket file. These configuration options are specified in the my.cnf file in the data directory.
- Each server must be configured to access data from a different shared location (i.e. each server must use a different data directory).