MySQL troubleshooting

Just in case you are facing downtime issues on MySQL on CentOS try these.

Check if disk is full

  • df -h

if disk is full check which folder is occupying lot of space.

  • cd /
  • du -skh *

Then go into individual folders to check if files can be deleted. If mysql/ folder looks like culprit, below steps might be useful.

If mysqld.log is big, trim it.

  • sudo echo -n > mysqld.log

In case there are 1.1GB files with sequence file numbers, e.g. xxx.00001, xxx.00002 etc, in /var/lib/mysql. Delete them.

  • cd /var/lib/mysql/
  • sudo service mysql stop
  • sudo rm -f xxx.0*
  • sudo service mysql start

If mysql is not allowing you to stop, kill it.

  • sudo kill -9 <<process_id_of_mysql>>
  • sudo rm -f xxx.err
  • sudo service mysql start

If mysql says Starting MySQL.The server quit without updating PID file try these

  • mysql_install_db
  • sudo service mysql start

If none of these work, dont loose faith.. Ask Google.

Still issues? ask a DBA.

Still issues? prepare to put down your papers.

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