Over time, Lemmy instances are going to keep aquiring more, and more data. Even if, in the best case, they are not caching content and they are just storing the data posted to communities local to the server, there will still be a virtually limitless growth in server storage requirements. Eventually, it may get to a point where it is no longer economically feesible to host all of the infrastructure to keep expanding the server’s storage. What happens at this point? Will servers begin to periodically purge old content? I have concerns that there will be a permanent horizon (as Lemmy becomes more popular, the rate of growth in storage requirements will also increase, thereby reducing the distance to this horizon) over which old – and still very useful – data will cease to exist. Is there any plan to archive this old data?
I’m not really sure that a K/V service is a more scalable option than Postgres for storing text posts and the like. If you’re not performing complex queries or requiring microsecond latencies then Postgres doesn’t require that much compute or memory.
People can get unnecessary scared of relational databases if they’ve had bad experiences with databases that are used poorly, but attempting to force relational data into a K/V can lead to the application layer essentially just doing a less efficient job of the same types of queries that the database would normally handle. Maybe there’ll be some future need to offload post and comment bodies into object storage or something but that seems incredibly premature.
Object storage for pictrs is definitely a fantastic addition, though.