If you use a dedicated host, you might as well abandon self hosted. HE is nice for small setups with the HA built in for extra fun, but once you scale, it might not be able to cope and you'll need real hardware. You're running a heavy-ish java engine plus two databases after all.

I'd be interested to know what type of scale needs a real hardware for engine, rather 100 vms or 1000 vms? it may be about the hosts number?