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17.3.2.1 MySQL Cluster Configuration — Basic Example »
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17.3.2. MySQL Cluster Configuration Files

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17.3.2.1. MySQL Cluster Configuration — Basic Example
17.3.2.2. Recommended Starting Configurations for MySQL Cluster NDB 6.2 and Later
17.3.2.3. The MySQL Cluster Connectstring
17.3.2.4. Defining Computers in a MySQL Cluster
17.3.2.5. Defining a MySQL Cluster Management Server
17.3.2.6. Defining MySQL Cluster Data Nodes
17.3.2.7. Defining SQL and Other API Nodes in a MySQL Cluster
17.3.2.8. MySQL Cluster TCP/IP Connections
17.3.2.9. MySQL Cluster TCP/IP Connections Using Direct Connections
17.3.2.10. MySQL Cluster Shared-Memory Connections
17.3.2.11. SCI Transport Connections in MySQL Cluster
17.3.2.12. Configuring MySQL Cluster Parameters for Local Checkpoints
17.3.2.13. Configuring MySQL Cluster Send Buffer Parameters

Configuring MySQL Cluster requires working with two files:

  • my.cnf: Specifies options for all MySQL Cluster executables. This file, with which you should be familiar with from previous work with MySQL, must be accessible by each executable running in the cluster.

  • config.ini: This file, sometimes known as the global configuration file, is read only by the MySQL Cluster management server, which then distributes the information contained therein to all processes participating in the cluster. config.ini contains a description of each node involved in the cluster. This includes configuration parameters for data nodes and configuration parameters for connections between all nodes in the cluster. For a quick reference to the sections that can appear in this file, and what sorts of configuration parameters may be placed in each section, see Sections of the config.ini File.

Caching of configuration data.  Beginning with MySQL Cluster NDB 6.4.0, MySQL Cluster uses stateful configuration. The global configuration file is no longer read every time the management server is restarted. Instead, the management server caches the configuration the first time it is started, and thereafter, the global confiuration file is read only when one of the following items is true:

  • The management server is started using --initial option.  In this case, the global configuration file is re-read, any existing cache files are deleted, and the management server creates a new configuration cache.

  • The management server is started using --reload option.  In this case, the management server compares its cache with the global configuration file. If they differ, the management server creates a new configuration cache; any existing configuration cache is preserved, but not used. If the management server's cache and the global configuration file contain the same configuration data, then the existing cache is used, and no new cache is created.

  • No configuration cache is found.  In this case, the management server reads the global configuration file and creates a cache containing the same configuration data as found in the file.

Configuration cache files.  Beginning with MySQL Cluster 6.4.0, the management server by default creates configuration cache files in a directory named mysql-cluster in the MySQL installation directory. (If you build MySQL Cluster from source on a Unix system, the default location is /usr/local/mysql-cluster.) This can be overridden at run time by starting the management server with the --configdir option. Configuration cache files are binary files named according to the pattern ndb_node_id_config.bin.seq_id, where node_id is the management server's node ID in the cluster, and seq_id is a cache idenitifer. Cache files are numbered sequentially using seq_id, in the order in which they are created. The management server uses the latest cache file as determined by the seq_id.

Note

It is possible to roll back to a previous configuration by deleting later configuration cache files, or by renaming an earlier cache file so that it has a higher seq_id. However, since configuration cache files are written in a binary format, you should not attempt to edit their contents by hand.

For more information about the --configdir, --initial, and --reload options for the MySQL Cluster management server, see Section 17.4.4, “ndb_mgmd — The MySQL Cluster Management Server Daemon”.

We are continuously making improvements in Cluster configuration and attempting to simplify this process. Although we strive to maintain backward compatibility, there may be times when introduce an incompatible change. In such cases we will try to let Cluster users know in advance if a change is not backward compatible. If you find such a change and we have not documented it, please report it in the MySQL bugs database using the instructions given in Section 1.7, “How to Report Bugs or Problems”.