Before starting a backup, make sure that the cluster is properly configured for performing one. (See Section 25.6.8.3, “Configuration for NDB Cluster Backups”.)

The START BACKUP command is used to create a backup, and has the syntax shown here:

START BACKUP [backup_id]
    [encryption_option]
    [wait_option]
    [snapshot_option]

encryption_option:
ENCRYPT [PASSWORD=password]

password:
{'password_string' | "password_string"}

wait_option:
WAIT {STARTED | COMPLETED} | NOWAIT

snapshot_option:
SNAPSHOTSTART | SNAPSHOTEND

Successive backups are automatically identified sequentially, so the backup_id, an integer greater than or equal to 1, is optional; if it is omitted, the next available value is used. If an existing backup_id value is used, the backup fails with the error Backup failed: file already exists. If used, the backup_id must follow immediately after the START BACKUP keywords, before any other options are used.

In NDB 8.0.22 and later, START BACKUP supports the creation of encrypted backups using ENCRYPT PASSWORD=password. The password must meet all of the following requirements:

When ENCRYPT PASSWORD='password' is used, the backup data record and log files written by each data node are encrypted with a key derived from the user-provided password and a randomly-generated salt using a key derivation function (KDF) that employs the PBKDF2-SHA256 algorithm to generate a symmetric encryption key for that file. This function has the form shown here:

key = KDF(random_salt, password)

The key so generated is then used to encrypt the backup data using AES 256 CBC inline, and symmetric encryption is employed for encrypting the backup fileset (with the generated key).

Starting with NDB 8.0.24, the PASSWORD option can be omitted from encryption_option. In this case, the management client prompts the user for a password.

It is possible using PASSWORD to set an empty password ('' or ""), but this is not recommended.

An encrypted backup can be decrypted using any of the following commands:

NDB 8.0.24 and later supports the additional commands listed here:

See the descriptions of these programs for more information, such as additional options that may be required.

The wait_option can be used to determine when control is returned to the management client after a START BACKUP command is issued, as shown in the following list:

WAIT COMPLETED is the default.

A snapshot_option can be used to determine whether the backup matches the state of the cluster when START BACKUP was issued, or when it was completed. SNAPSHOTSTART causes the backup to match the state of the cluster when the backup began; SNAPSHOTEND causes the backup to reflect the state of the cluster when the backup was finished. SNAPSHOTEND is the default, and matches the behavior found in previous NDB Cluster releases.

If both a wait_option and a snapshot_option are used, they may be specified in either order. For example, all of the following commands are valid, assuming that there is no existing backup having 4 as its ID:

START BACKUP WAIT STARTED SNAPSHOTSTART
START BACKUP SNAPSHOTSTART WAIT STARTED
START BACKUP 4 WAIT COMPLETED SNAPSHOTSTART
START BACKUP SNAPSHOTEND WAIT COMPLETED
START BACKUP 4 NOWAIT SNAPSHOTSTART

The procedure for creating a backup consists of the following steps:

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:

$> 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:

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

$> ndb_mgm -e "ABORT BACKUP backup_id"