Here is a small sql commando to show the largest mysql tables on your system.
SELECT
table_schema as `Database`,
table_name AS `Table`,
round(((data_length + index_length) / 1024 / 1024), 2) `Size in MB`
FROM information_schema.TABLES
ORDER BY (data_length + index_length) DESC
LIMIT 10;
Thank you http://www.mysqlperformanceblog.com/2008/02/04/finding-out-largest-tables-on-mysql-server/ for the code.