My multi-tenant web app does this but I don't know if you'd call 100 unique users a day "at scale". I believe it will be helpful if it's necessary to separate

My multi-tenant web app does this but I don't know if you'd call 100 unique users a day "at scale". I believe it will be helpful if it's necessary to separate customers into "pods" as we grow. The main advantage I feel we get however is that it was quite easy to write a wrapper around mysqldump to retrieve data for development purposes. I worked at a company that stored all customer data in a single database. The performance was comparable but the agility was poor. Firstly, you had to download all customer data to get a copy to debug a problem. This was a security concern I had, and eventually we had to build a serialisation format to retrieve the "slice" of data we needed. This tool needed frequent updating as new tables were added. You might argue that we should just try to imagine the bug and recreate it but we have some pretty complicated data structures which can make investigations very hard.