On accessing the Plesk control panel you may receive the “PleskFatalException Unable to connect to database: Too many connections” error message and this is caused when the mysql connections on the server are exceeded than the specified value.
ERROR: PleskFatalException Unable to connect to database: mysql_connect() : Too many connections 0: /usr/local/psa/admin/plib/common_func.php3:190 psaerror (string 'Unable to connect to database: mysql_connect() Too many connections')
The temporary solution is to restart the Mysql service, and the permanent solution is to increase the max_connections value in the mysql configuration.
SSH to your server and restart the mysql service
# /etc/init.d/mysqld restart
If the problem is occurring quite frequently, you should increase the max_connections value in the my.cnf file. To check the existing max_connections value
# mysqladmin variables -uadmin -p`cat /etc/psa/.psa.shadow` \ | grep max_connections
To increase the max_connections value, edit the /etc/my.cnf file
# vi /etc/my.cnf
and set the following parameter
max_connections = new_value
where, new_value should be the number higher than the existing mysql connections retrieved from the previous command.
Save the file and restart the Mysql service for the changes to take affect:
# /etc/init.d/mysqld restart