What is the difference between a Virtual Domain and a normal one?

[Greg]

Poste's implementation seems to be designed around only supporting one domain well (from what I've looked at).

Is it best to a have a poste container per domain?

Are there any downsides of using virtual domains instead of a distinct container per domain? (For example, delivery rates?)

I tried searching the documentation and issues and couldn't find my information about this.

[SH]

No, you should be using only one container for all domains. Every delivery domain is virtual.

The only "real" domain used is something like mail.example.com which is assigned to mailserver itself and used as mx for all virtual domains.