Feasible to use a single server for Authentication and SQL queries?

I do not know why Epic Forums does not have a Network Forum section so I am asking here. I was wondering if anyone has experience using only a single server for intermittent SQL queries. I was planning on setting up just one server for logging in, and infrequently saving inventory info and when a player exits session. It would be a 500/50mbps connection. I have heard of a single server handling thousands of SQL databases, spanning 1000+ clients, with less bandwidth. The single server would have a backup server setup.

The regular game session would use the listen-server model, with matchmaking/discovery through steam api. Would this be a feasible option for a smaller game?