Best of luck with your business, but I believe you've been misled about that "only needing one database server" bit. MongoDB makes replication easy (though not

Best of luck with your business, but I believe you've been misled about that "only needing one database server" bit. MongoDB makes replication easy (though not necessarily reliable), but its structure all but ensures that you will need to take advantage of that replication far earlier than you would have had you gone with a traditional database. For example, my employer's production stack requires three Mongo servers. Stack Overflow, which has a much greater volume of data and gets far more traffic, uses MSSQL and consequently only needs one server.