How to monitor MySQL space?

Question

I downloaded a VM image of a web application that uses MySQL.

How can I monitor its space consumption and know when additional space must be added?

Answer 1

du -s /var/lib/mysql/* | sort -nr

Result

34128   /var/lib/mysql/db_name1
33720   /var/lib/mysql/db_name2
29744   /var/lib/mysql/db_name3
26624   /var/lib/mysql/db_name4
16516   /var/lib/mysql/db_name5

Thsi will show as descending order in kb