Additional languages
« 15.6.2 ndbd — The Storage Engine Node Process
15.6.4 ndb_mgm — The Management Client Process »
Section Navigation      [Toggle]

15.6.3. ndb_mgmd — The Management Server Process

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.

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 15.4.4.2, “The Cluster Connectstring”, for information about using connectstrings. Section 15.6.5, “Command Options for MySQL Cluster Processes”, 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 15.4, “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 15.7, “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.