Could you build these as stand-alone "Hive" servers?
I am curious as DayZ servers often have persistant hives. You can have a different character server-toserver but your bank and other benefits are usuable on other servers.
I am just thinking if you could hive servers to provide different functions. One server is the chat and other functions - one is combat - one is the market and so on. I am curious due to the benefits this would have for development.
The short answer is obviously: yes.
But your question has some implied facets to it that are rather complex. For one thing, at the moment there's no such thing as server persistence, because as described the state of the system is likely being stored locally. So currently, the only persistence that can exist is what each individual player's client remembers (like the state of character slots, for example, which they seem to have hacked into the client-side software).
More generally, XMPP servers can be clustered with known techniques, and most seem to have the ability to have modular components added to them to add functionality. Stating for the record that this is as much a developer-preference thing as anything else, I believe that if the project continues along and Codewalker continues to add both functionality and scalability, the most likely architecture he'd pursue would be one where the primary communications hub was clustered if necessary (XMPP servers can handle a lot more connected clients than City of Heroes mapservers and whole game servers could ever handle, so clustering might not be necessary from a performance perspective), and a separate, modular system for adding enhanced functionality that could plug into the base XMPP server's message processing.
However, I have a feeling that most of the work Codewalker will be focused on in the short term is enabling client-side features that require limited or no central processing to make work, which means server-side concerns will probably be theoretical for a long while. It depends on how much functionality is already there, but knowing Codewalker I believe he's releasing this as soon as he believes he has sufficient functionality to be workable with minimal feature holes between the functionality. That almost certainly means there's tons more things he can do: he wouldn't wait to release until every last thing was working.
Put it this way: before we see "real" combat, I suspect we'll see "fake" combat first. From what I can deduce from what's being described, I'll bet Codewalker is (if he hasn't already, of course) dying to make powers work at least
visually, and perhaps even physically (as in: using the local client-side physics engine). Its a lot easier, albeit not easy, for Codewalker to add functionality that would allow us to activate a power, like "powexec_name Power_Blast target_name" and have the software send that message to the XMPP server, so that both you and everyone else sees the animation, FX, and sound effect played for that power when its directed at "target_name." Nothing would happen, because there's no central server keeping track of health bars, so you can't defeat the target or even hurt it, but you could see a power "work" in that sense. You might even be able to trigger knockback, although there are security/griefing issues to resolve when allowing that player to player (player to NPC, on the other hand, seems at least plausible).
That could happen without a central server, and therefore without having to solve the problem of central mapservers or even a combat engine. But since Codewalker has already stated he doesn't have movement mode bits working yet for Fly, its probable this is a City of Jabber 2.0 or even 3.0 feature. But I know Codewalker can do it with the system he's
not-describing, and its the logical outgrowth of the work he's done with Icon and the XMPP system, and its a very likely waypoint between here and eventual combat.