We recently migrated WHMCS to latest CentOS 7 server with cPanel. The WHMCS ClientArea showed White screen when “Client logins were used”. We found that the server had MySQL strict mode enabled which was causing this problem. I disabled MySQL strict mode as below : Edited /usr/my.cnf and changed below value : sql_mode=NO_ENGINE_SUBSTITUTION,NO_AUTO_CREATE_USER Restarted MySQL… Continue reading Disable MySQL strict mode!
After upgrading MySQL binaries mysqld will not start at all any more and shows below error : CT-1977-bash-4.1# service mysqld start Another MySQL daemon already running with the same unix socket. Starting mysqld: [FAILED] CT-1977-bash-4.1# MySQL service does not shut down gracefully during the OS reboot, leaving the old /var/lib/mysql/mysql.sock such that mysqld will not… Continue reading Another MySQL daemon already running with the same unix socket.
This should be handled on a case by case basis, but if you are using the default MySQL table type of MyISAM (which is the default storage engine unless changed or specified differently) here are a few options: The myisamchk utility can be run from a command line to checks, repairs, or optimizes tables. It… Continue reading Repairing MySQL tables that will not open.
How MySQL Uses Memory This page lists some of the ways that the mysqld server uses memory, and associated mysqld variable names Memory Use MySQL 5.0 Memory Use MySQL 4.1 MySQL Optimization which covers: – Optimization Overview – Optimizing SELECT and Other Statements – Locking Issues – Optimizing Database Structure – Optimizing the MySQL Server… Continue reading MySQL Optimization / Repair Information
Due to differing needs and requirements this is difficult to answer except on a case by case basis. The MySQL website has a section regarding general security of a MySQL database available here: http://dev.mysql.com/doc/refman/5.0/en/security.html Additionally some good practices are: Verify your root MySQL account password is set the test account and database that were created… Continue reading Securing MySQL.
1. Copying from the mysql directory By default, MySQL databases on servers that use Linux are stored in the following directory: /var/lib/mysql/ If you shut down the mysqld service first, you can copy your databases to an example /backup directory using the following command: cp –Rp /var/lib/mysql/*.* /backup The –R switch for the cp command means recursive, which you… Continue reading How do I backup MySQL in Linux?
If you’ve upgraded MySQL via WebHost manager, the downgrade process is slightly more complex than the upgrade. This tutorial mainly covers a downgrade from 4.1 to 4.0, but also applies to downgrading from 5.x to 4.x. *Back up all databases before proceeding, as all existing databases will be deleted! 1. Uninstall existing MySQL packages: rpm… Continue reading Downgrading MySQL to 4.x – cPanel
It’s common that when moving a cPanel account between servers with differing software versions, the version numbers (specifically MySQL) on the side of cPanel still reflect those of the old server. This can be changed by editing the version files for the account that was moved: The files holding the version numbers are located in:… Continue reading Wrong Version Numbers in cPanel