When running MySQL on macOS (OS X), the default data directory location varies depending on the installation method:


Homebrew installation: /usr/local/var/mysql
DMG package installation: /usr/local/mysql/data
MAMP installation: /Applications/MAMP/db/mysql


To verify your exact data directory location, connect to MySQL and run:

SHOW VARIABLES LIKE 'datadir';
Each database is stored as a separate directory containing these key files:
db_name/
    db_name.frm (table structure)
    db_name.ibd (InnoDB data for MySQL 5.6+)
    db_name.MYD (MyISAM data)
    db_name.MYI (MyISAM index)

Follow these steps to move MySQL databases between macOS servers:
# 1. Stop MySQL service
sudo mysql.server stop

# 2. Archive the database directory
tar -czvf mysql_data_backup.tar.gz /path/to/mysql/data/directory

# 3. Transfer the archive to new server
scp mysql_data_backup.tar.gz user@newserver:/tmp/

# 4. On new server, stop MySQL and backup existing data
sudo mv /path/to/mysql/data /path/to/mysql/data_backup

# 5. Extract and set permissions
sudo tar -xzvf /tmp/mysql_data_backup.tar.gz -C /path/to/mysql/
sudo chown -R _mysql:_mysql /path/to/mysql/data
sudo chmod -R 750 /path/to/mysql/data

# 6. Start MySQL service
sudo mysql.server start
For InnoDB tables using the system tablespace (ibdata1), you must:

Migrate the entire data directory
Ensure identical innodb_file_per_table settings
Maintain the same MySQL major version

After migration, connect to MySQL and verify:
SHOW DATABASES;
USE migrated_db;
SHOW TABLES;
SELECT COUNT(*) FROM important_table;
Check the error log for any issues:
tail -f /usr/local/var/mysql/hostname.err
For smaller databases or cross-version migrations, consider using mysqldump:
# Export
mysqldump -u root -p --databases db1 db2 > backup.sql

# Import
mysql -u root -p < backup.sql
This method avoids file permission issues and is more version-flexible.

On macOS systems with default MySQL installations (including Homebrew installations), the database files are typically stored in:
/usr/local/var/mysql/
You can confirm the exact data directory location by checking the MySQL configuration or running this command:
mysql -uroot -p -e "SHOW VARIABLES LIKE 'datadir';"
Sample output:
+---------------+------------------------+
| Variable_name | Value                  |
+---------------+------------------------+
| datadir       | /usr/local/var/mysql/  |
+---------------+------------------------+
The data directory contains several important components:

Database directories (one per database, named after the database)
System tables (mysql, performance_schema, sys)
Log files (error log, binary logs)
Configuration files (my.cnf)

Follow these steps to properly migrate MySQL data between macOS servers:
# 1. Stop MySQL on both servers
sudo /usr/local/bin/mysql.server stop

# 2. Archive the data directory on source server
tar -czvf mysql_data_backup.tar.gz /usr/local/var/mysql/

# 3. Transfer the archive to the new server
scp mysql_data_backup.tar.gz user@newserver:/tmp/

# 4. On destination server, remove existing data (if any)
sudo rm -rf /usr/local/var/mysql/*

# 5. Extract the archive
sudo tar -xzvf /tmp/mysql_data_backup.tar.gz -C /usr/local/var/mysql/

# 6. Set proper permissions
sudo chown -R _mysql:_mysql /usr/local/var/mysql/
sudo chmod -R 755 /usr/local/var/mysql/

# 7. Start MySQL service
sudo /usr/local/bin/mysql.server start
For Homebrew installations, you might need to adjust the data directory path in the MySQL plist file:
# For Homebrew services
brew services stop mysql
# Edit the plist file if needed
nano /usr/local/opt/mysql/homebrew.mxcl.mysql.plist
After migration, verify data integrity by checking:
mysqlcheck -uroot -p --all-databases --check-upgrade
And confirm all databases are accessible:
mysql -uroot -p -e "SHOW DATABASES;"