SQL tables are growing rapidly, such as manage them well?

you can set up a cronjob to (modified to suit) with:-

0 0 1 * * /usr/bin/mysql -D asteriskcdrdb -ppassword -u user -e "DELETE FROM cdr WHERE calldate  < (NOW() - INTERVAL 1 MONTH)";/usr/bin/mysql -D asteriskcdrdb -ppassword -u user -e "DELETE FROM cel WHERE eventtime  < (NOW() - INTERVAL 1 MONTH)"