As a System Administrator I don’t prefer to use / directory to store MySQL data files. Each time when I install MySQL for a production server, I tried to use secondary disk for storing application and database file. In that way I always change the default data directory of MySQL to secondary disk mounted on system.
Mostly MySQL uses /var/lib/mysql directory as default data directory for Linux based systems. Which are going to change to another location in this article.
Instruction’s to Change Default MySQL Data Directory:
Follow the below steps to make all the changes. In some cases service name, default data directory or MySQL configuration file path change. So use all the command as per you system settings.
1. Stop MySQL
Before making any changes, first make sure to stop mysql service
# service mysqld stop
2. Change Data Directory
Now copy default MySQL data directory (/var/lib/mysql) to other location as per your requirement. Also set the required MySQL ownership on new directory location. As per below command, we are relocating data directory to /data/mysql.
# cp -rap /var/lib/mysql /data/mysql # chown mysql.mysql /data/mysql
Now edit MySQL default configuration file /etc/my.cnf and update values of datadir and socket variable.
Change From: datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sockChange To: datadir=/data/mysql socket=/data/mysql/mysql.sock
3. Start MySQL
After making all above changes. finally start MySQL service. Now it will use new data directory path
# service mysqld start
This article has been tested with CentOS 6.5 with MySQL 5.5.37. If you face any issue during MySQL startup check mysql log file /var/log/mysqld.log for any errors.
After changing data directory, is it necessary to check used mysql ports before restart services?
hi ,
i did the above procedure in RHEL 7 , the files were copied also i changed the ownership of mysql data directory which has the same permission as the original file but still getting an error when i restart the mysql service
stating “Job for mysqld.service failed. See ‘systemctl status mysqld.service’ and ‘journalctl -xn’ for details”
please help thanks!
What is output of “systemctl status mysqld.service”?
Is any idea how its work on centos 7.cause my mysqld cannot start after done these change.thanks.
Is there any reason to move the .sock file?
I mean it can be kept in the original location, right?
Hi,
Thanks for the article !
I’d like to add something because I was facing an issue while trying to connect to the database after I made the changes listed above.
When I tried to connect to the database with the mysql client, I had this error :
“ERROR 2002 (HY000): Can’t connect to local MySQL server through socket ‘/var/lib/mysql/mysql.sock’ (2)”
The problem where that the mysql client is using by default the /var/lib/mysql/mysql.sock socket.
In the /etc/my.cnf file, I just added a client section specifying the socket :
[client]
socket=/data/mysql/mysql.sock
Hope this will help,
Cheers !
John,
You have to relink the sock file, which is under the new data directory.
Here is the sample:
ln -s /data/mysql/mysql.sock /var/lib/mysql/mysql.sock
Thank you it worked for me
Shouldn’t the Change To: datadir=/data/mysql in this example?
Hi Darius,
Yes, We need to change it. We have corrected typo.
I tried to do the same in CENTOS 6.4 and https://www.centos.org/forums/viewtopic.php?t=6732 this link worked perfectly!