Recently I was investigating how big my innodb buffer pool should be. While looking for more detailed info I came across this really handy mysql query which gives in result number of GB to which you should set your innodb_buffer_pool_size
SELECT CEILING(Total_InnoDB_Bytes*1.6/POWER(1024,3)) RIBPS FROM (SELECT SUM(data_length+index_length) Total_InnoDB_Bytes FROM information_schema.tables WHERE engine='InnoDB') A;
To query what is your current data usage you can use the following
SELECT (PagesData*PageSize)/POWER(1024,3) DataGB FROM (SELECT variable_value PagesData FROM information_schema.global_status WHERE variable_name='Innodb_buffer_pool_pages_data') A, (SELECT variable_value PageSize FROM information_schema.global_status WHERE variable_name='Innodb_page_size') B;
With this knowledge you should not have any problems with tuning your mysql 😉