{"id":334,"date":"2026-10-13T16:01:28","date_gmt":"2026-10-13T16:01:28","guid":{"rendered":"http:\/\/www.scmgalaxy.com\/tutorials\/2013\/05\/15\/mysql-basic-troubleshooting-guide\/"},"modified":"2026-10-13T16:01:28","modified_gmt":"2026-10-13T16:01:28","slug":"mysql-basic-troubleshooting-guide","status":"publish","type":"post","link":"https:\/\/www.devopsschool.com\/blog\/mysql-basic-troubleshooting-guide\/","title":{"rendered":"MySQL Basic Troubleshooting Guide: Service, Port 3306, Logs, and Crash Repair"},"content":{"rendered":"
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\"mysql-troubleshooting\"\/<\/figure>\n<\/div>\n\n\n

Originally published on 2013-05-15; fully revised and updated.<\/em><\/p>\n\n\n\n

MySQL incidents are often a mix of service state, configuration mistakes, port conflicts, and storage pressure. This guide gives a practical troubleshooting sequence for DevOps and operations teams, with command examples you can run on Linux hosts and notes for legacy setups still using older init scripts.<\/p>\n\n\n\n

Fast triage workflow<\/h2>\n\n\n\n

Use this order to avoid jumping between unrelated checks and to quickly isolate whether the problem is process, network, config, or storage related.<\/p>\n\n\n\n

\nflowchart TD\n    A[Locate mysql and mysqld binaries] --> B[Check mysqld service status]\n    B --> C{Running}\n    C -- no --> D[Read error log and my.cnf paths]\n    D --> E[Fix config, permissions, or disk issues]\n    E --> F[Start service again]\n    C -- yes --> G[Check port 3306 listener and socket]\n    G --> H{Conflict found}\n    H -- yes --> I[Stop conflicting process or change port]\n    H -- no --> J[Test login and mysqladmin status]\n    J --> K[Review slow queries and host performance]\n<\/pre>\n\n\n\n
Confirm MySQL binaries and service state<\/h2>\n\n\n\n
Start by confirming the client binary location, then verify whether mysqld<\/strong> is running.<\/p>\n\n\n
which mysql\nlocate mysql\nps -ef | grep [m]ysqld<\/code><\/span><\/pre>\n\n\n
Service control commands differ by init system. Many older guides use SysV-style commands; modern distributions usually use systemd<\/strong>.<\/p>\n\n\n\n
Task<\/th>systemd-based Linux<\/th>SysV init (legacy)<\/th><\/tr><\/thead>
Check status<\/td>systemctl status mysqldor systemctl status mysql<\/td>service mysqld status<\/td><\/tr>
Start \/ stop \/ restart<\/td>systemctl start|stop|restart mysqld<\/td>\/etc\/init.d\/mysqld start|stop|restartor service mysqld start|stop|restart<\/td><\/tr>
If service is missing<\/td>Validate installed package\/service name<\/td>Legacy registration sometimes used chkconfig with scripts under \/etc\/init.d<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
Check port 3306 binding and process conflicts<\/h2>\n\n\n\n
If MySQL reports Address already in use<\/strong>, verify which process owns TCP 3306.<\/p>\n\n\n
ss -ltnp | grep :3306\nlsof -i TCP:3306\nnetstat -lp | grep 3306\nnetstat -tap | grep mysql\nps -aux | grep mysql<\/code><\/span><\/pre>\n\n\n
Command<\/th>Best use<\/th>What to look for<\/th><\/tr><\/thead>
ss -ltnp<\/td>Modern listener check<\/td>PID\/program bound to 3306<\/td><\/tr>
lsof -i TCP:3306<\/td>Process-to-port mapping<\/td>Whether mysqld owns the socket<\/td><\/tr>
netstat -lp \/ -tap<\/td>Legacy systems<\/td>Listener and owning process<\/td><\/tr>
ps … grep mysqld<\/td>Process existence check<\/td>Running daemon and possible duplicates<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
If 3306 is not listening under mysqld, either MySQL is down or configured for another port\/socket in my.cnf<\/strong>.<\/p>\n\n\n\n
Find my.cnf and verify critical settings<\/h2>\n\n\n\n
When startup or connectivity fails, confirm configuration file location and validate key directives.<\/p>\n\n\n
whereis my.cnf\nlocate my.cnf\nfind \/ -name my.cnf\nstrace mysql \";\"<\/span> 2<\/span>>&1<\/span> | grep cnf<\/code><\/span>Code language:<\/span> JavaScript<\/span> (<\/span>javascript<\/span>)<\/span><\/small><\/pre>\n\n\n
Platform<\/th>Common default option files (original guide)<\/th><\/tr><\/thead>
Linux<\/td>\/etc\/my.cnf\/etc\/mysql\/my.cnf\/usr\/etc\/my.cnf~\/.my.cnf<\/td><\/tr>
Windows<\/td>C:\\Windows\\my.iniC:\\Windows\\my.cnfC:\\my.iniC:\\my.cnfC:\\Program Files\\MySQL\\MySQL Server 5.5\\my.iniC:\\Program Files\\MySQL\\MySQL Server 5.5\\my.cnf<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
Important parameters to verify in my.cnf<\/strong>:<\/p>\n\n\n\n