NDB Cluster Log Messages • START BACKUP  is used to perform an online backup in the  ndb_mgm  client; the  ABORT BACKUP command is used to cancel a backup already in progress. For more information, see Section 23.5.8, “Online Backup of NDB Cluster” . •The  CLUSTERLOG  command is used to perform various logging functions. See Section 23.5.3, “Event Reports Generated in NDB Cluster” , for more information and examples.  NODELOG DEBUG  activates or deactivates debug printouts in node logs, as described previously in this section. •For testing and diagnostics work, the client supports a  DUMP  command which can be used to execute internal commands on the cluster. It should never be used in a production setting unless directed to do so by MySQL Support. For more information, see MySQL NDB Cluster Internals Manual. 4444 23.5.2 NDB Cluster Log Messages 23.5.2.1 NDB Cluster: Messages in the Cluster Log This section contains information about the messages written to the cluster log in response to different cluster log events. It provides additional, more specific information on  NDB  transporter errors. The following table lists the most common  NDB  cluster log messages. For information about the cluster log, log events, and event types, see Section 23.5.3, “Event Reports Generated in NDB Cluster” . These log messages also correspond to log event types in the MGM API; see The Ndb_logevent_type Type, for related information of interest to Cluster API developers. Table 23.52 Common NDB cluster log messages Log Message Description Event Name Event Type Priority Severity Node mgm_node_id : Node data_node_id Connected The data node having node ID node_id  has connected to the management server (node mgm_node_id ). Connected Connection 8 INFO Node mgm_node_id : Node data_node_id Disconnected The data node having node ID data_node_id has disconnected from the management server (node mgm_node_id ). Disconnected Connection 8 ALERT Node data_node_id : Communication to Node api_node_id closed The API node or SQL node having node ID api_node_id is no longer communicating with data node data_node_id . CommunicationClosed Connection 8 INFO Node data_node_id : Communication The API node or SQL node having node ID CommunicationOpened Connection 8 INFO