If you go strictly by that rule of accommodating an addition 10%, here is my suggestion:
SELECT CONCAT(CEILING(RIBPS/POWER(1024,pw)),SUBSTR(' KMGT',pw+1,1))
Recommended_InnoDB_Buffer_Pool_Size FROM
(
SELECT RIBPS,FLOOR(LOG(RIBPS)/LOG(1024)) pw
FROM
(
SELECT SUM(data_length+index_length)*1.1*growth RIBPS
FROM information_schema.tables AAA,
(SELECT 1 growth) BBB
WHERE ENGINE='InnoDB'
) AA
) A;
This will produce exactly what you need to set innodb_buffer_pool_size in /etc/my.cnf
. If you want to account for 25% increase in data and indexes over time, please change (SELECT 1 growth) BBB
to (SELECT 1.25 growth) BBB
Recently, I answered another question like this in the DBA StackExchange.