You could still scale the dashboard server as it's plain LAMP stack, so you can even separate the DB on one (or multiple servers) and the Apache/PHP on one (or

You could still scale the dashboard server as it's plain LAMP stack, so you can even separate the DB on one (or multiple servers) and the Apache/PHP on one (or multiple, load balanced servers). I never tested such setup, as a single server can handle a lot of traffic and don't have yet any enterprise client (that I know of) which has performance issues.