Physical backups

The MySQL / MariaDB integration only supports logical dumps. Physical backups are done by stopping the server and backing up the data directory directly with Plakar’s built-in filesystem connector.

Physical backups are faster to restore than logical dumps and capture everything: all databases, configuration files, and InnoDB redo logs. They are version-locked: the backup must be restored with the same MySQL major version.

For logical dumps using mysqldump or mariadb-dump, see Logical backups with SQL dumps.

• Root or mysql system user access on the backup host.
• The MySQL data directory location (default /var/lib/mysql, check datadir in my.cnf if it differs).

The safest method. Stop MySQL, back up the data directory, then restart:

$ sudo systemctl stop mysql.service
$ sudo plakar at /var/backups backup /var/lib/mysql
$ sudo systemctl start mysql.service

Minimize downtime using FLUSH TABLES WITH READ LOCK. All writes are blocked for the duration:

$ mysql -u root -p << 'EOF'
FLUSH TABLES WITH READ LOCK;
SYSTEM sudo plakar at /var/backups backup /var/lib/mysql
UNLOCK TABLES;
EOF

$ plakar at /var/backups ls

Stop MySQL, move aside the existing data directory, restore, fix permissions, and restart:

$ sudo systemctl stop mysql.service
$ sudo mv /var/lib/mysql /var/lib/mysql.old
$ sudo plakar at /var/backups restore -to /var/lib/mysql <snapshot_id>
$ sudo chown -R mysql:mysql /var/lib/mysql
$ sudo systemctl start mysql.service

$ plakar at /var/backups restore -to ./mydb <snapshot_id>
$ sudo chown -R 999:999 ./mydb
$ docker run --rm -ti \
  -v ./mydb:/var/lib/mysql \
  mysql:<version>

Replace <version> with the same MySQL major version that was running when the backup was taken.

Physical backups must be restored with the same MySQL major version. For cross-version restores, use a logical backup instead.

Ensure the backup includes all InnoDB files: ibdata*, ib_logfile* (or #ib_redo* on MySQL 8.0.30+), and individual .ibd files. InnoDB performs crash recovery automatically on startup.

MEMORY tables are not stored on disk and will be empty after a physical restore. Use a logical backup if you need to preserve their contents.

The examples above use /var/backups as the Kloset store. Any supported store backend can be used instead. See Create a Kloset store for details.

• Logical backups with SQL dumps
• MySQL / MariaDB integration reference
• MySQL backup methods