Blizzard Sharding and Server Performance

WoW Classic WoW Classic General Discussion
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I decided to make a post here, for those that are curious. Note, I don’t work at Blizzard so I can only make educated guesses. But I’ve been doing this kind of work for a long time. But so far, I haven’t been wrong yet.

First off. Data center model (one physical server per realm - the same one the private servers use) is gone. It’s on the cloud. So what does that mean?

It used to be one machine per realm. Now it’s X number of machines per realm. Why on earth would they do that? Because to run software, running it using the combined power of X mini servers, is cheaper than managing and upgrading one mega server. It’s cost.

So, if that’s the case, the end result should be the same right? Meaning, why can’t the X mini servers handle the load? The answer is that they can. But Blizzard won’t. Why? Cost. You see, the beauty of the cloud is to save money, by saying “Hey as you your software gets more volume, we’ll automatically add more mini servers so everything is peachy.” So, Blizzard runs everything at a minimum. It’s the 80/20 rule. Keep things running for the scenarios 80% of the time. The other 20% are outliers. As a company if you worry about outliers, you’ll be wasting money. Cost.

So, if in the cloud, if performance automatically “scales up”, then it should never lag right? You see, the issue is that it takes time for new servers to come up. . WoW is spikey in volume in nature. So if 100 alliance fight 100 horde in hillsbrad all of a sudden, the volume will spike and the servers will blow up before more of them are active and ready to handle more load.

When I said, that Vanilla needed to be translated into Retail at the outset of Classic, the below is what I meant. And it’s why Classic took as long as it did. And it’s also why I say Classic is going to have it’s own “numbers” and not be able to truly replicate 1.12 even if Blizzard does have its numbers.

First off. Forget about the old concept of “realms”. They don’t exist anymore. There is no one machine that holds everything necessary to run WoW. Instead, you have a “combat engine”, or “location engine”, or “equipment engine”, or “raiding engine”, or whatever WoW is made of - one can only guess. Each “engine” will sit on their own server. Each is “realm” agnostic. They don’t give a flying hoot if you’re Durotan or Blackrock.

That’s what Blizzard meant by “pieces” of the puzzle. Each “engine” is a piece of the puzzle. Think of Vanilla as puzzle already put together so that it’s really just a picture sitting on one server. Where as Retail is a bunch of puzzle pieces sitting on different servers that gets put together dynamically on some other server which returns the picture. Now, wtf would you split an entire game into 100 pieces? Software engineering has changed a ton the last 14 years. I’ll leave at that. But, google monolith vs micro services if you so please. But, again - cost.

Ok. So here comes my educated guess part.

So if there are no realm servers, what’s the deal with “realms”? After doing away with dedicated servers, I’m guessing Blizzard came up with a technical concept - realms. Realms are now nothing but logical groups of people who prefer to play together. Each “people grouping” will point to a dedicated group “engines” - the sample being the lame list I gave above.

So what does this have to do with sharding? Well, remember that realms are now logical groups of people that use the same set of “engines”? When traffic gets heavy, what do you do? All you gotta do is move some people from one “realm” to another. i.e. one group to another, which then by default moves them from one engine to another - reducing traffic.

What this means is that sharding will ALWAYS be in the game. It’s just a matter of how high a setting Blizzard wants to set it to trigger that sharding. Like they said, it’s all configurable.

It’s a long read. But hope this helps.

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There’s a difference between virtual machines and in the cloud.

It does, and this is why the fear mongering is so unwarranted until we see exactly how they’ll be tuning sharding.

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Great post Xanthak. I suspected as much myself.

Here’s an article…an interview with the head IT guy who also talks about their technology changes over the years.

(add https://…I cannot post links)
www.gamesindustry.biz/articles/2018-08-13-after-fourteen-years-of-world-of-warcraft-infrastructure-isnt-a-limitation

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I got a question, in one of their documentaries, they showed one of the server ‘farms’? and pulled out a server blade, do they not use farms or blades like that anymore then?

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That would be a no sir.

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They do, but the way they function is different.

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They use cloud services now.

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No they certainly do not. Please show me the cloud service I can sign up to if I want to create a WoW realm?

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no i have read that is how they do the servers now too, i just don’t know if that means less server farm places or what though,lol.

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Just ignore him. He’s done nothing but troll from the beginning.

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Hmm… so blizzard doesn’t still have racks of servers out there?

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A very interesting (and one would assume) fact-filled post. Especially since none of us work for Blizzard and know for sure what their servers and services look like exactly…

Thank you.

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I believe AT&T is still doing their hosting.

From the article I linked above:
“When World of Warcraft shipped it was on single realms that were completely independent from all other realms. Now we’re on a much more cloud-based infrastructure, which didn’t exist in 2004 and is now the industry standard.”

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Translation, every realm had dedicated physical servers. That it no longer the case.

There are a huge number of implications to that but it does not mean that WoW servers are the same as google docs because they used the word cloud when they were described.

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I’m not sure where that even comes from. A “cloud service” does not necessarily have to mean something for an end-user. Many pieces of server software could also be considered “services”.

Even non-gaming companies use “cloud services” on servers in their corporate headquarters that multiple satellite locations around the globe can use.

I’m not sure what you expect to gain for arguing a point that is not really debatable and is actually a point that favors sharding. There really is no point to it.

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That’s why I’m wondering why the whole cloud service thing even has come into the discussion. It seems like a buzz word that is being used incorrectly.

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:sweat_smile:

It isn’t really, though. The servers being in a cloud infrastructure could easily be considered a “cloud service” that is more or less internal to Blizzard, the servers then allow connections from the outside.

In computer terms, nearly any program running on a computer could be considered a “service” depending on how it’s run and structured.

Xanthak made a very good informative post that actually demonstrates how sharding would be used and needed and why.

Bashing he and Brockthorn over semantics isn’t really worth it. At least, not in my opinion.

I agree with much that you say, but I can’t agree with you here.

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I was overly argumentative with Xanthak’s post.

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Thanks for the informative post. I had no idea about the technical aspects of sharding, and how blizzard now run servers. I hope that they can keep the cap very high, so that events like world bosses and the AQ door opening can be experienced by as many people as possible, hopefully everyone who wants to be involved.

While I am very excited to play classic WoW, I think the fact that it is back-engineered is causing a lot of unavoidable problems. I don’t envy the developers, especially because there are a lot of people (myself included) who are very particular about how the game should be. The more technical information I learn, however, the more I feel I should not be that hard on the people who are working on the game.

(Side note)
I hope classic will show the greedy corporate side of the gaming industry that caring about your consumers is a good idea, and that not handing your players everything can make games a lot more fun.

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The thing is that since they’ve implemented this new cloud-based (rather than single-blade-based) system, it doesn’t seem that it can handle having more than a moderate amount of players in any one area. Starting with the launch of WoD and throughout that expansion, up until sharding was introduced with Legion, it’s very noticeable how current WoW chokes under the slightest bit of stress.

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