If your mysql eats enormous amount of space, check if binary logging is on
Check if binlog creating is on
show variables like 'log_bin';
If it is on it will create lots of bin log files on mysql/data folder.
If you have only simple mysql database without master / slaves / replication stuff, you have opportunity to get free space and block creating bin logs in the future.
Purge existing bin logs
PURGE BINARY LOGS TO 'mysql-bin.010'; PURGE BINARY LOGS BEFORE '2019-04-02 22:46:26';
Block creating binlogs
// /etc/mysql/my.cnf [mysqld] disable_log_bin
and restart mysql server