MySQL Enterprise Backup User's Guide (Version 3.12.5)
You can specify mysqlbackup options either on the command line or as configuration parameters inside a configuration file. This section describes the use of configuration files.
In general, mysqlbackup follows the
mysql style of processing configuration
options: [mysqlbackup] and
[client] group options are passed as
command-line options. Any command-line options that you specify
override the values from the configuration file, and in the case
of duplicate options, the last instance takes precedence.
mysqlbackup also reads options in the
[mysqld] group to detect parameters related to
the source repository when no connection to
mysqld is available.
Within mysqlbackup option names, dashes
(-) and underscores (_) may be used
interchangeably, similar to mysqld parameters
that use this same convention (see
Using Options on the Command Line in the MySQL Reference
Manual for details). The MySQL server's reference manual typically
lists the parameter names with underscores, to match the output of
the SHOW VARIABLES statement.
mysqlbackup reads the location of the MySQL data to back up from (in order of priority):
The connection information from the running database, whenever possible. Thus, in most cases, you can avoid specifying most options on the command line or in a configuration file.
Parameters you specify on the mysqlbackup command line. You can specify certain options for individual backup jobs this way.
The MySQL configuration file (by default,
my.cnf on Unix and
my.ini on Windows). The parameters are
searched for first under the [mysqlbackup]
group, then under the [client] group. You
can put common parameters that apply to most of your backup
jobs into the configuration file.
Because mysqlbackup does
not overwrite any files during the initial backup step,
the backup directory must not contain any old backup files.
mysqlbackup stops when asked to create a file
that already exists, to avoid harming an existing backup. For
convenience, specify the --with-timestamp option,
which always creates a unique timestamped subdirectory for each
backup job underneath the main backup directory.
Each set of backup data includes a configuration file,
backup-my.cnf, containing a minimal set of
configuration parameters. The mysqlbackup
command generates this file to record the settings that apply to
this backup data. Subsequent operations, such as the
apply-log process, read options from this file to
determine how the backup data is structured.
Example 15.1 Example backup-my.cnf file
Here is an example backup-my.cnf file
generated by mysqlbackup:
[mysqld] innodb_data_file_path=ibdata1:256M;ibdata2:256M:autoextend innodb_log_file_size=256M innodb_log_files_in_group=3
All paths in the generated backup-my.cnf file
point to a single backup directory. For ease of verification and
maintenance, you typically store all data for a backup inside a
single directory rather than scattered among different
directories.
During a backup, the configuration parameters that are required
for later stages (such as the restore operation) are recorded in
the backup-my.cnf file that is generated in
the backup directory. Only the minimal required parameters are
stored in backup-my.cnf, to allow you to
restore the backup to a different location without extensive
changes to that file. For example, although the
innodb_data_home_dir and
innodb_log_group_home_dir options can go into
backup-my.cnf, they are omitted when those
values are the same as the backup-dir value.