And the techniques in the article are basically how we did it. (I say “we” but I’m just a system administrator who got to work with some cool people at Turbine.)
As Eumenes notes, the Asheron’s Call engine was significantly ahead of its time with the seamless zoning. The cost was high, though — we needed quite a few servers to run a world, I think many more than our competitors. There are business reasons why we weren’t quite as cost-conscious as we perhaps should have been.
The other factor involved in determining how often you persist is item duplication. If it’s possible to transfer an item between players without persisting state, and if there are known exploits that crash servers (not world, but individual servers), you wind up with an exploit that can duplicate items. But I’m sure that’s just hypothetical.
As Eumenes notes, the Asheron’s Call engine was significantly ahead of its time with the seamless zoning. The cost was high, though — we needed quite a few servers to run a world, I think many more than our competitors. There are business reasons why we weren’t quite as cost-conscious as we perhaps should have been.
The other factor involved in determining how often you persist is item duplication. If it’s possible to transfer an item between players without persisting state, and if there are known exploits that crash servers (not world, but individual servers), you wind up with an exploit that can duplicate items. But I’m sure that’s just hypothetical.