We all know that the mysql folder contains my. INI file: Modify the datadir file to change the storage location of the database and table. It is stored in C:/ProgramData/MySQL Server 5.5/Data/by default in windows /, for example, if we change datadir to I:/data, we may encounter the following situations: www.2cto.com 1. re-open mysql administrator or the corresponding command line, we found that the data storage location is still the original directory. The reason is that the mysql service has not been stopped, my. ini is not re-read when it is started. We can stop it by using the command line, or stop the mysql service in the control panel -- manage -- service, and then enable it; www.2cto.com 2. When you restart the mysql service, error 1067 is displayed. You can view the error log file in the new directory where datadir is located. The reason is that the performance_schema and mysql folders in the original datadir directory were not copied to the new directory! Copy them.