RDS MySQL Storage Full ... When DB usage is low

Question

I am getting Storage Full on one of my staging RDS tables and trying to figure out which DB/Tables is large ... but found that they are actually very small:

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;

SELECT table_schema "DB Name", 
Round(Sum(data_length + index_length) / 1024 / 1024, 1) "DB Size in MB" 
FROM   information_schema.tables 
GROUP  BY table_schema; 

Largest DB is only 16.7 MB so whats filling up my 10GB RDS?

From the pattern I am suspecting some cron ... which indeed there is a cron inserting data ... but as you can see from the table/db sizes its not that large ... what else can be filling up my RDS? Does backup/logs etc count as storage?

UPDATE:

I notice that on 26 July there is is spike in DB free storage and I tried looking into General Query log to determine what happened. I notice theres

 PURGE BINARY LOGS TO 'mysql-bin-changelog.097019'

Wonder if it fails to purge logs subsequently?

Answer 1

SHOW BINARY LOGS;

to see how many, and of what size, your logs. Then we can discuss purging some of them.

SHOW VARIABLES LIKE '%log%'

Chase down the files that are mentioned; show us the output so we can discuss sizes.

The "general log" can grow very fast; turn it off when not using it. And get rid of its log(s).

The "slow log" is very good for debugging performance problems. Use pt-query-digest to summarize it, then toss it.

The "error log" should not be big. If it is, then you probably have worse problems.

What is the current setting for expire_logs_days?