Blizzard Developer on Sharding, Layers, and The Blood Moon Event - Season of Discovery
Blizzard Developer Tom Ellis shared some interesting insight on Twitter covering the history of Sharding, Layering, and how layering issues are working on being resolved. Many players have been sharing negative experiences with layering during the Blood Moon Event in Stranglethorn Vale on Season of Discovery, hopefully a fix will be implemented soon.
Tom Ellis
Caveat, there's no announcement of any changes in this, this is all just fascinating info if you're into that sort of thing.
Layering, Sharding, let's dive in.
So, in what we call Mainline (modern game, latest expansion) we use tech called Sharding ever since Warlord of Draenor.
Once upon a time, a realm ran one copy of each zone locally on it's own hardware, if you ran after someone and they crossed into another zone, you followed them, it was all running in the same place, you could kite mobs across zones, escort quests had NPCs pathing across zone boundaries.
Problem, as hardware improved and performance improvements were made, expansion after expansion we raised the cap on the number of concurrent players we allowed logged in. If everyone wants to play on Tich, and we have the technical capacity to lower queue times, why wouldn't you? Ah, but the realm still only ran one copy of the world, eventually the realm has so many people on it that if even a small percentage of them congregate in the same place its going to be way more than the CPU core that's running that zone can handle, in comes the lag, you can multithread to your hearts content, eventually you're going to have a single thread bottleneck that will limit what you can do.
This all came to a head in Warlords of Draenor when in the face of a very successful launch the starting zones in WoD were completely unable to handle the load they faced.
