4.2.2 Backup Repository Parameters

The following parameters are supported in configuration files under the [mysqlbackup] group. The underscore characters in parameter names can be replaced with dashes and treated as synonyms, similar to mysqld parameters that use this same convention. (See Using Options on the Command Line in the MySQL Reference Manual for details.) The documentation typically lists the names with underscores, to match the output of the SHOW VARIABLES statement.

The parameters marked as having No Default value are specified through my.cnf files, command-line parameters, or can be obtained automatically once the mysqlbackup command establishes a database connection.

backup_dir

The location under which backup destination files go. Typically retrieved automatically through the database connection. Must be specified if a database connection is not available. Same as the --backup-dir command-line option.

backup_innodb_data_home_dir

Specifies the directory where backup InnoDB data files live. Usually same as backup-dir, but can be different.

This parameter together with backup_innodb_data_file_path determines where the InnoDB data files (such as ibdata1, ibdata2, ...) are stored inside the backup directory structure.

This parameter is applicable only for backup operations, not restore.

For the backup operations (such as backup, backup-and-apply-log, backup-to-image), the value of the backup destination directory is derived as follows:

  • If backup_innodb_data_home_dir is not specified, it inherits the value of backup-dir.

  • If backup_innodb_data_home_dir is a relative path, that path is located relative to (that is, underneath) the backup-dir value.

  • An backup_innodb_data_home_dir of "" refers to the / root directory.

  • If backup_innodb_data_home_dir is an absolute path, its value is used as-is.

To make it easy to relocate the backup directory and avoid editing the backup-my.cnf file, the backup operation writes this value into backup-my.cnf only if it is different than the backup-dir value, and using a relative path if possible.

For backup-to-image operations, the final value of the backup_innodb_data_home_dir option must be a relative path, so that the single-file backup is machine-independent.

backup_innodb_data_file_path

Specifies InnoDB data file names and sizes. Examples:

ibdata1:32M;ibdata2:32M:autoextend
/abs/path/ibdata1:32M:autoextend
innodb-dir/ibdata1:32M:autoextend

This parameter together with backup_innodb_data_home_dir determines where the InnoDB data files (such as ibdata1, ibdata2, ...) live in the backup repository.

Within the backup directory, any data files specified with relative paths are located relative to the backup_dir path. Any data files specified with absolute paths are placed inside the backup_innodb_data_home directory.

When the parameter is not specified, it inherits the value from the value of the innodb_data_file_path option. If both source and destination attempt to use an absolute path that resolve to the same files, the backup is cancelled.

To specify absolute paths for InnoDB datafiles in backup, you must also set the backup_innodb_data_home option to "".

backup_innodb_log_group_home_dir

Specifies where backup InnoDB logs live. Usually the same as backup-dir, but can be different.

The names of the log files are fixed and not reconfigurable.

This parameter is applicable only for backup operations (not restore).

The backup operation uses this value and writes it as innodb_log_group_home_dir=value in backup-my.cnf.

For copy-back and apply-log operations, innodb_log_group_home_dir in backup-my.cnf is treated in a way that is compatible with how it was created.

backup_innodb_log_files_in_group

Specifies the number of InnoDB log files in backup before being rotated. Example: 5.

Usually same as innodb_log_files_in_group, but can be different.

The value for this parameter is derived as:

  • Specified backup_innodb_log_files_in_group value from command line or configuration file.

  • Else innodb_log_files_in_group value from the database connection, if available.

  • Else the innodb_log_files_in_group value from the command line or configuration file.

backup_innodb_log_file_size

Specifies maximum single InnoDB log file size in backup before switching to next log file. Example: 20M.

Usually the same as innodb_log_file_size, but can be different.

The value for this parameter is derived as:

  • Specified backup_innodb_log_file_size value from command line or configuration file.

  • Else innodb_log_file_size value from database connection, if available.

  • Else specified innodb_log_file_size value from command line or configuration file.

incremental-backup-dir

Specifies backup destination directory for incremental backup. Default: No Default.

backup-image

Specifies the path for a single-file backup. Specifying any non-seekable device is also OK. The value - specifies standard output (stdout).

If the path is relative, it is interpreted relative to the backup-dir value. The extension .mbi extension that we use in documentation examples is not required.