@gotwf The configuration is as productive as possible. The forum runs on 6 dedicated servers with mongo replication, redis cluster and balancer at the nginx level. But at peak loads, mongo just does not leave a chance and even there were cases when mongo-service ended with an error.
In addition, I noticed that chats are very slow and I would like to optimize them through separate tables in the database. Chats are the weakest part in NodeBB right now. And I'm surprised and a bit frustrated that there is no way to convert from one database to another. I personally like Postgres much more than Mongo because I have more experience with Postgres.
That's why I'm even ready to financially support development of this tool, because I think that such functionality should be part of NodeBB core.