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Connection and privileges needed

Percona XtraBackup needs to be able to connect to the database server and perform operations on the server and the datadir when creating a backup, when preparing in some scenarios and when restoring it. In order to do so, there are privileges and permission requirements on its execution that must be fulfilled.

Privilege refers to the operations that a system user is permitted to do in the database server. They are set at the database server and only apply to users in the database server.

Permissions are those which permits a user to perform operations on the system, like reading, writing or executing on a certain directory or start/stop a system service. They are set at a system level and only apply to system users.

When xtrabackup is used, there are two actors involved: the user invoking the program - a system user - and the user performing action in the database server - a database user. Note that these are different users in different places, even though they may have the same username.

All the invocations of xtrabackup in this documentation assume that the system user has the appropriate permissions, and you are providing the relevant options for connecting the database server - besides the options for the action to be performed - and the database user has adequate privileges.

Connect to the server

The database user used to connect to the server and its password are specified by the --user and --password option:

$ xtrabackup --user=DVADER --password=14MY0URF4TH3R --backup \
--target-dir=/data/bkps/

If you don’t use the --user option, Percona XtraBackup will assume the database user whose name is the system user executing it.

Other connection options

According to your system, you may need to specify one or more of the following options to connect to the server:

Option Description
-port Use this port when connecting to the database with TCP/IP
-socket Use this socket when connecting to the local database.
-host Use this host when connecting to the database server with TCP/IP

These options are passed to the mysql child process without alteration, see mysql --help for details.

Note

In case of multiple server instances, the correct connection parameters (port, socket, host) must be specified in order for xtrabackup to talk to the correct server.

Privileges needed

Once connected to the server, in order to perform a backup you need READ and EXECUTE permissions at a filesystem level in the server’s datadir.

The database user needs the following privileges to back up tables or databases:

  • RELOAD and LOCK TABLES (unless the --no-lock option is specified) in order to run FLUSH TABLES WITH READ LOCK and FLUSH ENGINE LOGS prior to start copying the files, and requires this privilege when Backup Locks are used

  • BACKUP_ADMIN privilege is needed to query the performance_schema.log_status table, and run LOCK INSTANCE FOR BACKUP, LOCK BINLOG FOR BACKUP, or LOCK TABLES FOR BACKUP.

  • REPLICATION CLIENT in order to obtain the binary log position,

  • CREATE TABLESPACE in order to import tables (see Restoring Individual Tables),

  • PROCESS in order to run SHOW ENGINE INNODB STATUS (which is mandatory), and optionally to see all threads which are running on the server (see FLUSH TABLES WITH READ LOCK option),

  • SUPER in order to start/stop the replication threads in a replication environment, use XtraDB Changed Page Tracking for Incremental Backups and for handling FLUSH TABLES WITH READ LOCK,

  • CREATE privilege in order to create the PERCONA_SCHEMA.xtrabackup_history database and table,

  • ALTER privilege in order to upgrade the PERCONA_SCHEMA.xtrabackup_history database and table,

  • INSERT privilege in order to add history records to the PERCONA_SCHEMA.xtrabackup_history table,

  • SELECT privilege in order to use --incremental-history-name or --incremental-history-uuid in order for the feature to look up the innodb_to_lsn values in the PERCONA_SCHEMA.xtrabackup_history table.

  • SELECT privilege on the keyring_component_status table to view the attributes and status of the installed keyring component when in use.

  • SELECT privilege on the replication_group_members table to validate if the instance is part of group replication cluster.

A SQL example of creating a database user with the minimum privileges required to take full backups would be:

mysql> CREATE USER 'bkpuser'@'localhost' IDENTIFIED BY 's3cr%T';
mysql> GRANT BACKUP_ADMIN, PROCESS, RELOAD, LOCK TABLES, REPLICATION CLIENT ON *.* TO 'bkpuser'@'localhost';
mysql> GRANT SELECT ON performance_schema.log_status TO 'bkpuser'@'localhost';
mysql> GRANT SELECT ON performance_schema.keyring_component_status TO bkpuser@'localhost';
mysql> GRANT SELECT ON performance_schema.replication_group_members TO bkpuser@'localhost';
mysql> FLUSH PRIVILEGES;

Query the privileges

To query the privileges that your database user has been granted at the console of the server execute:

mysql> SHOW GRANTS;

or for a particular user with:

mysql> SHOW GRANTS FOR 'db-user'@'host';

It will display the privileges using the same format as for the GRANT statement.

Note that privileges may vary across versions of the server. To list the exact list of privileges that your server support (and a brief description of them) execute:

mysql> SHOW PRIVILEGES;

See also

Permissions needed

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Last update: 2024-04-04