I have to worry about how the engine manages threading and network card allocations. A server cluster could have 10 network cards, but if the engine deems an area a unit of simulation and that means it gets threaded to only utilize one of the virtual machines in the cluster, then I have instantly locked my resource availability.
Example: Lets say there is a cluster with 3 physical servers that basically create 1 virtual machine. Each run quad core cpus at 2 Ghz with a 100mb network card and 8 gig of ram. ( I know not beefy servers but work for example here).
Basically that becomes a server with
24 ghz processing
24 gig of ram
300mb network stream
Using just for reference.
http://hewiki.heroengine.com/wiki/Sizing_for_productionYou get roughly 1,000 users per
10ghz
5 gig of ram
130 mb network
the vm machine cluster can handle about 2,000 users in general
if I have a large pvp area and 2,000 people decide to be in it (not all at same coordinate location but inside the 1 massive area spread out and around) at the same time. IE a few zerg guilds fighting over different areas in the map.
The server in general can handle it assuming the pvpArea can use all of the VMs resources. However if an area which is a "unit of simulation" can only run on 1 of the physical hardware pieces in the vm's cluster due to cpu threading, ram management, and network routing by the engine. Then the most I can have is about 800 users in my pvparea at any one given time. So I need to plan for that, build in some system to manage pvp player volumes, in my case really forced into a queue system that I would rather not use, build a system to kick inactives faster in the pvp than maybe in pve, and much more. I would probably also look at breaking the area up possibly into different areas and see if I could use some mount ranges, deep trenches etc to cut down on touching grids to help keep concurrently loaded areas down.
OR if an area isn't locked to 1 piece of hardware, and can use any of the 12 cores, 3 network cards, etc all at the same time, then all i have to worry about is making 1 large pvparea, spread the fighting out in that area to take advantage of the systems spatial awareness, etc. Cap my server worlds to 2,000 people, make use of areas with low traffic having possiblity to spin down, allowing the main pvpArea more resources. And just to be clear I would still build in the in-active timers, etc just wouldn't have to worry about queue systems, and having to build out for proxy node based combat system.
so depending on what a unit of simulation actually means when it comes to ability to utilize resources greatly alters how the entire game is built, managed, and advertised. Thus why I am here being the annoying newbie. I know there are a ton of different things, how combat is coded, how this and that. The base question still remains, when a single area is running does it consume resources from all physcial machines making up the overall VM OR does it get tied into a single physical machine that is part of that clustered VM?
Sorry to keep digging at this, but it's so important to the whole game design, that I can't really finalize world design till I get it nailed down.
Thank you all who put up with my walls of text and I appreciate all the help.