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MySQL 3.23, 4.0, 4.1 Reference Manual :: 15 MySQL Cluster :: 15.4 MySQL Cluster Programs :: 15.4.3 ndb_mgmd — The MySQL Cluster Management Server Daemon
15.4.4 ndb_mgm — The MySQL Cluster Management Client »
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15.4.3. ndb_mgmd — The MySQL Cluster Management Server Daemon

The management server is the process that reads the cluster configuration file and distributes this information to all nodes in the cluster that request it. It also maintains a log of cluster activities. Management clients can connect to the management server and check the cluster's status.

The following table includes command options specific to the MySQL Cluster management server program ndb_mgmd. Additional descriptions follow the table. For options common to all MySQL Cluster programs, see Section 15.4.21, “Options Common to MySQL Cluster Programs”.

Table 15.10. ndb_mgmd Command Line Options

Format Description Introduction Deprecated Removed
-f Specify the cluster configuration file; in NDB-6.4.0 and later, needs --reload or --initial to override configuration cache if present      
--daemon Run ndb_mgmd in daemon mode (default)      
--interactive Run ndb_mgmd in interactive mode (not officially supported in production; for testing purposes only)      
--mycnf Read cluster configuration data from the my.cnf file      
--no-nodeid-checks Do not provide any node id checks      
--nodaemon Do not run ndb_mgmd as a daemon      
--print-full-config Print full configuration and exit 4.1.14    

  • --config-file=filename, -c filename, -f filename

    Command-Line Format -f
      Permitted Values
    Type filename
    Default ./config.ini

    Instructs the management server as to which file it should use for its configuration file. By default, the management server looks for a file named config.ini in the same directory as the ndb_mgmd executable; otherwise the file name and location must be specified explicitly.

    The -f shortcut is available beginning with MySQL Cluster 4.1.8. This option also can be given as -c file_name, but this shortcut is obsolete and should not be used in new installations.

  • --daemon, -d

    Command-Line Format --daemon
      Permitted Values
    Type boolean
    Default TRUE

    Instructs ndb_mgmd to start as a daemon process. This is the default behavior.

  • --nodaemon

    Command-Line Format --nodaemon
      Permitted Values
    Type boolean
    Default FALSE
      Permitted Values
    Type (windows) boolean
    Default TRUE

    Instructs ndb_mgmd not to start as a daemon process.

  • --print-full-config, -P

    Version Introduced 4.1.14
    Command-Line Format --print-full-config
      Permitted Values
    Type boolean
    Default FALSE

    Shows extended information regarding the configuration of the cluster. With this option on the command line the ndb_mgmd process prints information about the cluster setup including an extensive list of the cluster configuration sections as well as parameters and their values. Normally used together with the --config-file (-f) option.

As of MySQL 4.1.5, it is no longer necessary to specify a connectstring when starting the management server. However, if you are using more than one management server, a connectstring should be provided and each node in the cluster should specify its node ID explicitly.

See Section 15.3.2.2, “The MySQL Cluster Connectstring”, for information about using connectstrings. Section 15.4.21, “Options Common to MySQL Cluster Programs”, describes other options for ndb_mgmd.

The following files are created or used by ndb_mgmd in its starting directory. From MySQL 4.1.5, the log and PID files are placed in the DataDir as specified in the config.ini configuration file. In the list that follows, node_id is the unique node identifier.

  • config.ini is the configuration file for the cluster as a whole. This file is created by the user and read by the management server. Section 15.3, “MySQL Cluster Configuration”, discusses how to set up this file.

  • ndb_node_id_cluster.log (was cluster.log in version 4.1.3) is the cluster events log file. Examples of such events include checkpoint startup and completion, node startup events, node failures, and levels of memory usage. A complete listing of cluster events with descriptions may be found in Section 15.5, “Management of MySQL Cluster”.

    When the size of the cluster log reaches one million bytes, the file is renamed to ndb_node_id_cluster.log.seq_id (was cluster.log.seq_id in version 4.1.3) where seq_id is the sequence number of the cluster log file. (For example: If files with the sequence numbers 1, 2, and 3 already exist, the next log file is named using the number 4.)

  • ndb_node_id_out.log (was node1.out in version 4.1.3) is the file used for stdout and stderr when running the management server as a daemon.

  • ndb_node_id.pid (was nodenode_id.pid in version 4.1.3) is the process ID file used when running the management server as a daemon.