Online Backup of NDB Cluster As is the case for the notification that the backup has started,  backup_id  is the unique identifier for this particular backup, and  node_id  is the node ID of the management server that is coordinating the backup with the data nodes. This output is accompanied by additional information including relevant global checkpoints, the number of records backed up, and the size of the data, as shown here: It is also possible to perform a backup from the system shell by invoking  ndb_mgm  with the  -e  or  -- execute  option, as shown in this example: shell>  ndb_mgm -e "START BACKUP 6 WAIT COMPLETED SNAPSHOTSTART" When using  START BACKUP  in this way, you must specify the backup ID. Cluster backups are created by default in the  BACKUP  subdirectory of the  DataDir  on each data node. This can be overridden for one or more data nodes individually, or for all cluster data nodes in the config.ini  file using the  BackupDataDir  configuration parameter. The backup files created for a backup with a given  backup_id  are stored in a subdirectory named  BACKUP- backup_id  in the backup directory. Cancelling backups.   To cancel or abort a backup that is already in progress, perform the following steps: ndb_mgm>  ABORT BACKUP  backup_id The number  backup_id  is the identifier of the backup that was included in the response of the management client when the backup was started (in the message  Backup  backup_id  started from node  management_node_id ). At this point, the management client has not yet received a response from the cluster data nodes to this request, and the backup has not yet actually been aborted. In this example, we have shown sample output for a cluster with 4 data nodes, where the sequence number of the backup to be aborted is  3 , and the management node to which the cluster management client is connected has the node ID  5 . The first node to complete its part in aborting the backup reports 4494 4. After the backup has been aborted, the management client reports this fact in a manner similar to what is shown here: 3. The management client acknowledges the abort request with  Abort of backup  backup_id ordered . 2. Execute this command: 1. Start the management client. Node 2: Backup 1 started from node 1 completed  StartGCP: 177 StopGCP: 180  #Records: 7362 #LogRecords: 0  Data: 453648 bytes Log: 0 bytes Node 1: Backup 3 started from 5 has been aborted. Error: 1321 - Backup aborted by user request: Permanent error: User defined error Node 3: Backup 3 started from 5 has been aborted. Error: 1323 - 1323: Permanent error: Internal error Node 2: Backup 3 started from 5 has been aborted. Error: 1323 - 1323: Permanent error: Internal error Node 4: Backup 3 started from 5 has been aborted. Error: 1323 - 1323: Permanent error: Internal error Note