How do I find the MySQL my.cnf location

Question

Is there a MySQL command to locate the my.cnf configuration file, similar to how PHP's phpinfo() locates its php.ini?

Answer 1

For Ubuntu 16: /etc/mysql/mysql.conf.d/mysqld.cnf

Answer 2

All great suggestions, in my case I didn't find it in any of those locations, but in /usr/share/mysql, I have a RHEL VM and I installed mysql5.5

Answer 3

There is no internal MySQL command to trace this, it's a little too abstract. The file might be in 5 (or more?) locations, and they would all be valid because they load cascading.

• /etc/my.cnf
• /etc/mysql/my.cnf
• $MYSQL_HOME/my.cnf
• [datadir]/my.cnf
• ~/.my.cnf

Those are the default locations MySQL looks at. If it finds more than one, it will load each of them & values override each other (in the listed order, I think). Also, the --defaults-file parameter can override the whole thing, so... basically, it's a huge pain in the butt.

But thanks to it being so confusing, there's a good chance it's just in /etc/my.cnf.

(if you just want to see the values: SHOW VARIABLES, but you'll need the permissions to do so.)

Answer 4

As noted by konyak you can get the list of places mysql will look for your my.cnf file by running mysqladmin --help. Since this is pretty verbose you can get to the part you care about quickly with:

$ mysqladmin --help | grep -A1 'Default options'

This will give you output similar to:

Default options are read from the following files in the given order:
/etc/my.cnf /etc/mysql/my.cnf /usr/local/etc/my.cnf ~/.my.cnf

Depending on how you installed mysql it is possible that none of these files are present yet. You can cat them in order to see how your config is being built and create your own my.cnf if needed at your preferred location.

Answer 5

You can use :

locate my.cnf
whereis my.cnf
find . -name my.cnf

Answer 6

This might work:

strace mysql ";" 2>&1  | grep cnf

on my machine this outputs:

stat64("/etc/my.cnf", 0xbf9faafc)       = -1 ENOENT (No such file or directory)
stat64("/etc/mysql/my.cnf", {st_mode=S_IFREG|0644, st_size=4271, ...}) = 0
open("/etc/mysql/my.cnf", O_RDONLY|O_LARGEFILE) = 3
read(3, "# /etc/mysql/my.cnf: The global "..., 4096) = 4096
stat64("/home/xxxxx/.my.cnf", 0xbf9faafc) = -1 ENOENT (No such file or directory)

So it looks like /etc/mysql/my.cnf is the one since it stat64() and read() were successful.