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Configure xtrabackup

All the xtrabackup configuration is done through options, which behave exactly like standard MySQL program options: they can be specified either at the command-line, or through a file such as /etc/my.cnf.

The xtrabackup binary reads the [mysqld] and [xtrabackup] sections from any configuration files, in that order. That is so that it can read its options from your existing MySQL installation, such as the datadir or some of the InnoDB options. If you want to override these, just specify them in the [xtrabackup] section, and because it is read later, it will take precedence.

You don’t need to put any configuration in your my.cnf. You can specify the options on the command-line. Normally, the only thing you may find convenient to place in the [xtrabackup] section of your my.cnf file is the target_dir option. This options adds a default path to the directory for backups.

The following is an example:

target_dir = /data/backups/

This manual assumes you do not have any file-based configuration for xtrabackup and shows the command-line options.

Please see the option and variable reference for details on all the configuration options.

The xtrabackup binary does not accept exactly the same syntax in the my.cnf file as the mysqld server binary does. For historical reasons, the mysqld server binary accepts parameters with a --set-variable=<variable>=<value> syntax, which xtrabackup does not understand. If your my.cnf file has such configuration directives, you should rewrite them in the --variable=value syntax.

System configuration and NFS volumes

The xtrabackup tool requires no special configuration on most systems. However, the storage where the --target-dir is located must behave properly when fsync() is called. In particular, we have noticed that if you mount the NFS volume without the sync option the NFS volume does not sync the data. As a result, if you back up to an NFS volume mounted with the async option, and then try to prepare the backup from a different server that also mounts that volume, the data might appear to be corrupt. Use the sync mount option to avoid this issue.

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Last update: 2024-06-12