I''d say this really depends on what your server does... for number crunching tasks, beowulf clusters rock, but I''ve no idea whether they''re viable for games - I guess not.
You should probably finish a single server first so you get an idea of what it has to do - however, always keep in mind that you''ll one day distribute the load.
There are several basic ways of distributing server load, one could call them horizontal and vertical splitting.
One method would be to distribute different tasks on different servers (one for an SQL-database, one for AI, one for world simulation), with the other method every server would take care of all those tasks, but limited to a certain area of the world.
cu,
Prefect
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