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MySQL 5.1 Reference Manual :: 20 MySQL Cluster :: 20.9 On-line Backup of MySQL Cluster :: 20.9.2 Using The Management Client to Create a Backup
20.9.3 ndb_restore — Restore a Cluster Backup »
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20.9.2. Using The Management Client to Create a Backup

Before starting a backup, make sure that the cluster is properly configured for performing one. (See Section 20.9.4, “Configuration for Cluster Backup”.)

Creating a backup using the management client involves the following steps:

  1. Start the management client (ndb_mgm), if it not running already.

  2. Execute the START BACKUP command. This produces several lines of output indicating the progress of the backup, as shown here: 

    ndb_mgm> START BACKUP
Waiting for completed, this may take several minutes
Node 2: Backup 1 started from node 1
Node 2: Backup 1 started from node 1 completed
 StartGCP: 177 StopGCP: 180
 #Records: 7362 #LogRecords: 0
 Data: 453648 bytes Log: 0 bytes
ndb_mgm>

    The first line printed indicates that the management client is waiting for the backup to be completed before returning control to the client. This behavior is the default for the START BACKUP command, but can be changed. To specify when START BACKUP command should return control to the client, append NOWAIT, WAIT STARTED, or WAIT COMPLETED to the command. The effects that each of these has differs as follows:

    • If NOWAIT is specified, the management client displays a prompt immediately, as seen here: 

      ndb_mgm> START BACKUP NOWAIT
ndb_mgm>

      In this case, the management client can be used even while it prints progress information from the backup process.

    • With WAIT STARTED the management client waits until the backup has started before returning control to the user, as shown here: 

      ndb_mgm> START BACKUP WAIT STARTED
Waiting for started, this may take several minutes
Node 2: Backup 3 started from node 1
ndb_mgm>

    • WAIT COMPLETED explicitly specifies the default behavior — that is, it causes the management client to wait until the backup process is complete before returning control to the user.

  3. When the backup has started the management client displays this message: 

    Backup backup_id started from node node_id

    backup_id is the unique identifier for this particular backup. This identifier is saved in the cluster log, if it has not been configured otherwise. node_id is the identifier of the management server that is coordinating the backup with the data nodes. At this point in the backup process the cluster has received and processed the backup request. It does not mean that the backup has finished. An example of this statement is shown here: 

    	
Node 2: Backup 1 started from node 1

  4. The management client indicates that the backup has completed with a message in the following format: 

    Backup backup_id started from node node_id completed

    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: 

    	
Node 2: Backup 1 started from node 1 completed
 StartGCP: 177 StopGCP: 180
 #Records: 7362 #LogRecords: 0
 Data: 453648 bytes Log: 0 bytes

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 as discussed in Identifying Data Nodes. 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.

To abort a backup that is already in progress:

  1. Start the management client.

  2. Execute this command: 

    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).

  3. The management client will acknowledge the abort request with Abort of backup backup_id ordered.

    Note

    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.

  4. After the backup has been aborted, the management client will report this fact in a manner similar to what is shown here: 

    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

    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 that the reason for the abort was due to a request by the user. (The remaining nodes report that the backup was aborted due to an unspecified internal error.)

    Note

    There is no guarantee that the cluster nodes respond to an ABORT BACKUP command in any particular order.

    The Backup backup_id started from node management_node_id has been aborted messages mean that the backup has been terminated and that all files relating to this backup have been removed from the cluster filesystem.

It is also possible to abort a backup in progress from a system shell using this command: 

shell> ndb_mgm -e "ABORT BACKUP backup_id"

Note

If there is no backup with ID backup_id running when an ABORT BACKUP is issued, the management client makes no response, nor is it indicated in the cluster log that an invalid abort command was sent.