accounting through detail module help

Hi, At present our radius servers getting traffic of more than 3 million users. We have only two radius servers and one mysql server active. The server crashing whenever more traffic comes. Due to mysql overload and slow I'm planning to use detail module for accounting and then take these details and parse then put in database using program/script. Does this helps? Is there any script already available in freeradius? Does palcing one more radius server and using mysql clustering helps? Please suggest. Thanks, Rams.