MySQL Service Won't Start: Troubleshooting

Common reasons MySQL fails to start and how to fix them.

Check Error Log

journalctl -u mysql --no-pager -n 50\ntail -50 /var/log/mysql/error.log

Common Causes

Disk Full

df -h

Free up space and try again.

Port Already in Use

ss -tuln | grep 3306

Kill the conflicting process.

Corrupted InnoDB Files

Try starting in recovery mode by adding to mysqld.cnf:

innodb_force_recovery = 1

Increase the value (1-6) if needed. Dump data and restore to a fresh installation.

Permission Issues

chown -R mysql:mysql /var/lib/mysql\nchmod 750 /var/lib/mysql