I don't remember all the details. But the triggering point was Amazon RDS: it was complaining every week that our DB consumed all available space and we had to

I don't remember all the details. But the triggering point was Amazon RDS: it was complaining every week that our DB consumed all available space and we had to increase the size and pay more with every week. Our DB and flow of data wasn't that big. I've spent some time investigating but haven't found anything: sum of sizes of all tables was quite moderate and much less than the size of the storage we paid Amazon for. I lacked both expertise and time to find out where the wasted space go. After I've set up Maria DB on a smallest Digital Ocean droplet, mysterious storage growth haven't repeated and the cheapest droplet had enough capacity to serve our needs for years. Also, there were 7-10 forgotten "test" server instances and other artifacts (buckets, domains, etc) on Amazon (I believe it's also quite common, especially in bigger companies).