If you run out of disk space on your server, it might be a good time to check your mysql binary logs. If there is really to much space used than just issue some SQL commands and you can delete them.
To delete all binary logs older than 7 days:
mysql> PURGE BINARY LOGS BEFORE DATE_SUB( NOW( ), INTERVAL 7 DAY);
To purge all logs before a specific date:
mysql> PURGE MASTER LOGS BEFORE ‘2008-01-01 00:00:00’;
To purge logs automatically (every Monday at 3am) you could use a Unix cron job:
0 3 * * mon mysql -uroot -e “PURGE BINARY LOGS BEFORE DATE_SUB( NOW( ), INTERVAL 7 DAY);”