MySQL 5.0 Reference Manual  /  ...  /  Defining a MySQL Cluster Management Server Defining a MySQL Cluster Management Server

The [ndb_mgmd] section is used to configure the behavior of the management server. [mgm] can be used as an alias; the two section names are equivalent. All parameters in the following list are optional and assume their default values if omitted.


If neither the ExecuteOnComputer nor the HostName parameter is present, the default value localhost will be assumed for both.

  • Id

    Effective VersionType/UnitsDefaultRange/ValuesRestart Type
    MySQL 5.0.0unsigned[none]1 - 63IS

    Each node in the cluster has a unique identity, which is represented by an integer value in the range 1 to 63 inclusive. This ID is used by all internal cluster messages for addressing the node.

    In MySQL 5.0.15 and later, NodeId is a synonym for this parameter, and is the preferred form. In MySQL Cluster NDB 6.2 and later, Id is deprecated in favor of NodeId for identifying management nodes.

  • NodeId

    Effective VersionType/UnitsDefaultRange/ValuesRestart Type
    MySQL 5.0.15unsigned[none]1 - 63IS

    Beginning with MySQL 5.0.15, NodeId is available as a synonym for Id.

    In MySQL Cluster NDB 6.2 and later, Id is deprecated in favor of NodeId for identifying management nodes.

  • ExecuteOnComputer

    Effective VersionType/UnitsDefaultRange/ValuesRestart Type
    MySQL 5.0.0name[none]...S

    This refers to the Id set for one of the computers defined in a [computer] section of the config.ini file.

  • PortNumber

    Effective VersionType/UnitsDefaultRange/ValuesRestart Type
    MySQL 5.0.0unsigned11860 - 64KS

    This is the port number on which the management server listens for configuration requests and management commands.

  • HostName

    Effective VersionType/UnitsDefaultRange/ValuesRestart Type
    MySQL 5.0.0name or IP address[none]...N

    Specifying this parameter defines the hostname of the computer on which the management node is to reside. To specify a hostname other than localhost, either this parameter or ExecuteOnComputer is required.

  • LogDestination

    Effective VersionType/UnitsDefaultRange/ValuesRestart Type
    MySQL 5.0.0{CONSOLE|SYSLOG|FILE}[see text]...N

    This parameter specifies where to send cluster logging information. There are three options in this regard—CONSOLE, SYSLOG, and FILE—with FILE being the default:

    • CONSOLE outputs the log to stdout:

    • SYSLOG sends the log to a syslog facility, possible values being one of auth, authpriv, cron, daemon, ftp, kern, lpr, mail, news, syslog, user, uucp, local0, local1, local2, local3, local4, local5, local6, or local7.


      Not every facility is necessarily supported by every operating system.

    • FILE pipes the cluster log output to a regular file on the same machine. The following values can be specified:

      • filename: The name of the log file.

      • maxsize: The maximum size (in bytes) to which the file can grow before logging rolls over to a new file. When this occurs, the old log file is renamed by appending .N to the file name, where N is the next number not yet used with this name.

      • maxfiles: The maximum number of log files.


      The default value for the FILE parameter is FILE:filename=ndb_node_id_cluster.log,maxsize=1000000,maxfiles=6, where node_id is the ID of the node.

    It is possible to specify multiple log destinations separated by semicolons as shown here:

  • ArbitrationRank

    Effective VersionType/UnitsDefaultRange/ValuesRestart Type
    MySQL 5.0.00-210 - 2N

    This parameter is used to define which nodes can act as arbitrators. Only management nodes and SQL nodes can be arbitrators. ArbitrationRank can take one of the following values:

    • 0: The node will never be used as an arbitrator.

    • 1: The node has high priority; that is, it will be preferred as an arbitrator over low-priority nodes.

    • 2: Indicates a low-priority node which be used as an arbitrator only if a node with a higher priority is not available for that purpose.

    Normally, the management server should be configured as an arbitrator by setting its ArbitrationRank to 1 (the default for management nodes) and those for all SQL nodes to 0 (the default for SQL nodes).

  • ArbitrationDelay

    Effective VersionType/UnitsDefaultRange/ValuesRestart Type
    MySQL 5.0.0milliseconds00 - 4294967039 (0xFFFFFEFF)N

    An integer value which causes the management server's responses to arbitration requests to be delayed by that number of milliseconds. By default, this value is 0; it is normally not necessary to change it.

  • DataDir

    Effective VersionType/UnitsDefaultRange/ValuesRestart Type
    MySQL 5.0.0path....N

    This specifies the directory where output files from the management server will be placed. These files include cluster log files, process output files, and the daemon's process ID (PID) file. (For log files, this location can be overridden by setting the FILE parameter for LogDestination as discussed previously in this section.)

    The default value for this parameter is the directory in which ndb_mgmd is located.

  • PortNumberStats

    Effective VersionType/UnitsDefaultRange/ValuesRestart Type
    MySQL 5.0.0unsigned[none]0 - 64KN

    This parameter specifies the port number used to obtain statistical information from a MySQL Cluster management server. It has no default value.


After making changes in a management node's configuration, it is necessary to perform a rolling restart of the cluster for the new configuration to take effect.

To add new management servers to a running MySQL Cluster, it is also necessary to perform a rolling restart of all cluster nodes after modifying any existing config.ini files. For more information about issues arising when using multiple management nodes, see Section, “Limitations Relating to Multiple MySQL Cluster Nodes”.

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