Recover Data from a MariaDB Server That Won't Start

Use this procedure when InnoDB corruption keeps MariaDB from starting and you need to get the data out. You start the server by hand with innodb_force_recovery, export every database, rebuild a clean data directory, and import the dump.

1. Stop the Service and Back Up the Data Directory

As root:

systemctl stop mariadb
cp -a /var/lib/mysql /root/mysql-datadir-backup-$(date +%F)

2. Start MariaDB in Recovery Mode

Start the server in the foreground. It skips the privilege tables (so you don't need passwords), doesn't listen on the network, and runs InnoDB in forced recovery:

mkdir -p /run/mysqld && chown mysql: /run/mysqld
mariadbd --user=mysql \
  --skip-grant-tables \
  --skip-networking \
  --skip-external-locking \
  --innodb-force-recovery=1 \
  --socket=/run/mysqld/mysqld.sock

If it won't start, stop it and try again with the next level up. Use the lowest level that lets the server start:

--skip-grant-tables disables all authentication. --skip-networking keeps that limited to local socket connections, so don't remove it.

3. Dump the Data

From a second shell, export what you can. Dump application databases individually so one bad table doesn't stop the whole export:

mariadb-dump --routines --events --triggers --databases <DB_NAME> > <DB_NAME>.sql

Or export everything at once, including user accounts stored in the mysql schema:

mariadb-dump --all-databases --routines --events --triggers > all-databases.sql

For a WordPress site, wp db export dump.sql from the site directory works too.

If a table fails to dump, try the next recovery level, or skip that table with --ignore-table=<DB_NAME>.<TABLE_NAME> and handle it separately.

4. Shut Down and Rebuild the Data Directory

Stop the recovery-mode server cleanly, then move the damaged data directory aside and create a fresh one:

mariadb-admin shutdown
mv /var/lib/mysql /var/lib/mysql.broken
mkdir /var/lib/mysql && chown mysql: /var/lib/mysql
mariadb-install-db --user=mysql --datadir=/var/lib/mysql
systemctl start mariadb

5. Restore and Recreate Users

Import the dump:

mariadb < <DB_NAME>.sql

If you dumped only application databases, recreate their users. See Create a Database and User.

CREATE USER '<DB_USER>'@'localhost' IDENTIFIED BY '<DB_PASSWORD>';
GRANT ALL PRIVILEGES ON <DB_NAME>.* TO '<DB_USER>'@'localhost';

6. Check and Optimize

Finally, verify every table and rebuild them for a clean start:

mariadb-check --check --auto-repair --all-databases
mariadb-check --optimize --all-databases

Confirm the application works before you delete the old data directory and the backup.