You are thinking of normalized ( bcnf if not 3nf) well architectures application storing structured data , unless the app is 100 million+ users or grew super fast 250TB size would be hard to get to .

Timeseries (like IoT you mentioned ) or binary blobs or logs or any other data in SQL storage that shouldn’t be really there can hit any size wouldn’t be all that interesting.

Can’t speak for OP, however managing data for few million user apps, what I have observed is most SQL stores hit single TB range and then start getting broken down into smaller dbs either coz now teams have grown want their own Micro-service or DB or infra wants easier to handle in variety of ways including Backup /recovery larger DBs are extremely difficult to get reasonable RTO/RPO numbers for.

If you want to store video data as BLOBs in a DB, you can get there easily.

Maybe not the best idea, I guess a file system would be better for that, and just use the DB for metadata.

But OTOH all the data is one place, so you just migrate the DB. Less to worry about.

I just looked up, all of English Wikipedia (including images) is barely even 100 GB ... crazy world we live in.

You wouldn’t say less to worry about when you have to do full backup or show recovery from backup within a set recovery time .

This one data store is easier is a myth , it just offloads complexity from developer to infra teams who are now provisioning premium NVMe storage instead of cold object stores for binary data .

Binary data is not indexed or aggregated in a SQL store there is no value in doing this is one place expect dev experience at the cost of infra team experience.

Super easy to generate arbitrary amounts of data if you start using postgres as a log, of any sort.

I worked for a company that had only a few thousand active customers yet had dozens of terabytes of data, for this reason.