xtrabackup supports taking partial backups when the innodb_file_per_table option is enabled. There are three ways to create partial backups:
- matching the tables names with a regular expression
- providing a list of table names in a file
- providing a list of databases
Do not copy back the prepared backup.
Restoring partial backups should be done by importing the tables,
not by using the
--copy-back option. It is not
recommended to run incremental backups after running a partial
Although there are some scenarios where restoring can be done by copying back the files, this may lead to database inconsistencies in many cases and it is not a recommended way to do it.
For the purposes of this manual page, we will assume that there is a database
test which contains tables named
If any of the matched or listed tables is deleted during the backup, xtrabackup will fail.
Creating Partial Backups¶
The first method involves the
xtrabackup --tables option. The option’s
value is a regular expression that is matched against the fully qualified
tablename, including the database name, in the form
To back up only tables in the
test database, you can use the following
$ xtrabackup --backup --datadir=/var/lib/mysql --target-dir=/data/backups/ \ --tables="^test[.].*"
To back up only the table
test.t1, you can use the following command:
$ xtrabackup --backup --datadir=/var/lib/mysql --target-dir=/data/backups/ \ --tables="^test[.]t1"
--tables-file option specifies a file that can contain multiple table
names, one table name per line in the file. Only the tables named in the file
will be backed up. Names are matched exactly, case-sensitive, with no pattern or
regular expression matching. The table names must be fully qualified, in
$ echo "mydatabase.mytable" > /tmp/tables.txt $ xtrabackup --backup --tables-file=/tmp/tables.txt
xtrabackup --databases accepts a space-separated list of the databases
and tables to backup in the format
databasename[.tablename]. In addition to
this list make sure to specify the
performance_schema databases. These databases are required when restoring
the databases using
$ xtrabackup --databases='mysql sys performance_schema ...'
xtrabackup --databases-file specifies a file that can contain multiple
databases and tables in the
databasename[.tablename] form, one element name
per line in the file. Only named databases and tables will be backed up. Names
are matched exactly, case-sensitive, with no pattern or regular expression
Preparing Partial Backups¶
$ xtrabackup --prepare --export --target-dir=/path/to/partial/backup
When you use the
xtrabackup --prepare option on a partial backup, you
will see warnings about tables that don’t exist. This is because these tables
exist in the data dictionary inside InnoDB, but the corresponding .ibd
files don’t exist. They were not copied into the backup directory. These tables
will be removed from the data dictionary, and when you restore the backup and
start InnoDB, they will no longer exist and will not cause any errors or
warnings to be printed to the log file.
An example of the error message you will see during the prepare phase follows.
InnoDB: Reading tablespace information from the .ibd files... 101107 22:31:30 InnoDB: Error: table 'test1/t' InnoDB: in InnoDB data dictionary has tablespace id 6, InnoDB: but tablespace with that id or name does not exist. It will be removed from data dictionary.
Restoring Partial Backups¶
Restoring should be done by restoring individual tables in the partial backup to the server.
It can also be done by copying back the prepared backup to a “clean”
datadir (in that case, make sure to include the
database). System database can be created with:
$ sudo mysql_install_db --user=mysql