How to move mysql datadir to new location

By default the mysql install the datadir at /var/lib/mysql. Unfortunately, people usually did partition their hard disk, or buy a new hard drive later. In such a case, you would like to move the *huge* datadir to another disk to both boost the speed by parallel in I/O and utilize space smartly. Here's what you should do:

1. Stop your mysql service.
   sudo /etc/init.d/mysql stop


2. Copying all files from old location to new location and preserver the ownership and timestamp information.
   sudo cp -r -p /var/lib/mysql /newlocation/


3. Update your mysql configuration file:
   sudo vim /etc/mysql/my.cnf
   

   datadir     = /newlocation/mysql #old: /var/lib/mysql
   



4. Update the second configuration file for apparmor:
   

     /newlocation/mysql/ r, #/var/lib/mysql/ r,
     /newlocation/mysql/** rwk, #/var/lib/mysql/** rwk,



5. (Optional) Rename the old folder to prevent confusing.
   sudo mv /var/lib/mysql /var/lib/mysql.bak


6. Restart your apparmor & mysql service.
   sudo /etc/init.d/apparmor reload
sudo /etc/init.d/mysql start


7. Delete the old location
   sudo rm -rf /var/lib/mysql.bak