公司价值观标语:Linden Lab's - Second Life Server Architecture Questions - PlayNoEvil Game Security News

ZDNet has an article on Second Life's server architecture... and it discusses its business model and other things.

Quick Aside - Linden Lab's Second Life has got to have the most Free Press Per Player/Subscriber of any online game.

The article raises some interesting questions about the scalability ofthe design as the average utilization is about 3 players per server asopposed to 116 players per server (a figure provided by Sony OnlineEntertainment for Everquest II).

Both games use a geographic model for distributing people. SecondLife's servers each are dedicated to 16 acres of space while inEverquest II, and most MMOs, there are multiple server clusers thatreplicate the world - think Disneyland, Disneyland Florida(Disneyworld), etc. that are essentially identical.

Second Life - 2579 servers - dual core AMD - total population 240,000 registered users, * substantially fewer paying users

Everquest II - ~1100 servers - dual CPU x86, 37 clusters, 20-40 CPUs - total pupulation 250,000+ subscribers

Conversely, Three Rings' Puzzle Pirates runs on 4 CPUs (servers?) withabout he same number of peak users as Second Life (it is worth notingthat Second Life has a very low peak utilization compared to its totalregistered users, at least when compared to Eve Online a while back).

- I can tell you which one I'd rather own stock in.

The comparisons are legitimate. First, from a business model point ofview, Second Life is closer to Puzzle Pirates than Everquest II. Bothare free to pay, pay-for-stuff business models. This free to play modelseems to run around a 1-3% conversion rate, though higher payments forthose who convert - averaging maybe $30/month for the paying players... your mileage may vary.

Linden Lab claims its infrastructure scales based on "land purchases", the primary business model that the company uses.

The business scalability problem with this is that land purchases arefar from uniform. Thus, many servers may not have nearly enough usersto pay for themselves. Linden compares its scalability to Google orYahoo, but both of those companies can pretty clearly determine howmuch revenue per server they are going to generate per month....multiply those darn ad impressions per server type (mail, search, etc.)by average revenue per ad impression and you've got a business model.For Linden Lab, since it is a land-rent model, the number of renters issome fraction of the game's total active population... Also, I ampretty sure that the rent is uniform even if the sales price isvariable, so Linden Lab doesn't benefit when "hot" real estate marketsoccur (except from the purchase of Linden's currency).

The technical scalability problem comes from the uniform geographymodel that the game uses. Second Life, and most games, have playershighly concentrated in some areas and none in others. Thus, "hot" partsof the game can suffer tremendous lag and eventual failure as thegame's total population increases. Unless Linden Lab can "split" aserver to serve smaller geographic tiles, this doesn't seem sensible.Also, it is not very dynamic - why have CPUs running when no one isthere?

Traditional MMOs can address this scaling problem by adding additionalservers to "hot" clusters/shards and encouraging players to move todifferent shards (limiting shard mobility is a key load management toolfor a traditional MMO). They also are gaining revenue from everysubscriber every month, providing a solid base for computing server andbandwidth and personnel costs.

Free-to-Play games are a rapidly growing portion of the online gamingmarket (with Asian games in the lead). These games must be much moresensitive to infrastructure costs than traditional MMOs since they donot have direct, self-sustaining revenue models. Games like PuzzlePirates and Second Life or, at the other extreme, Guild Wars need toplan and manage their infrastructure cost very carefully as they drivesuccess and profitability. 'Second Life': Don't worry, we can scale
By Daniel Terdiman
URL: http://news.zdnet.com/2100-1040_22-6080186.html
Last March, Cory Ondrejka, the chief technology officer at "SecondLife" publisher Linden Lab, bet a symbolic quarter that his virtualworld would within two years have more users than the wildly popularonline game "World of Warcraft."

The bet was certainly ambitious. After all, "WoW," as fans call it,currently has more than 6.5 million users. "Second Life" has 240,000registered users. But whether Linden Lab's virtual world can catch"WoW" isn't the most pressing question about the virtual world's futurefor some people familiar with its computer network.

"The underlying architecture of the Internet and of 'Second Life' is perfectly scalable."
--Linden Lab CEO Philip Rosedale Their concern is more abouttechnology: Can the computer network of "Second Life," using an unusualconfiguration that dedicates each server to a sliver of virtual realestate, scale with growing demand?

"Second Life" currently runs on 2,579 servers that use the dual-coreOpteron chip produced by AMD. Each server is responsible for anindividual "sim," or 16 acres of virtual "Second Life" land. At peakusage that means that each server is handling about three users.

"Most (massively multiplayer online games) have hundreds to thousandsof players per server machine," said Michael Sellers, who runs OnlineAlchemy, a provider of artificial-intelligence tools for online games."Is there a way they can achieve (significant) elements of scale? Ihaven't seen that."

There's little question that "Second Life" manages far fewer users perserver than other virtual worlds. Sony Online Entertainment's"EverQuest II," which has more than 250,000 users, runs on about 1,100dual-CPU, x86 (x86 is the processor architecture used by most AMD andIntel chips) servers spread across 37 clusters of 20 to 40 servers.Each of those handles around 116 users at peak usage, according tofigures provided by SOE.

Big bucks needed?
These wildly different figures have some observers scratching theirheads and wondering if Linden Lab is going to have to spend big to keepthe "Second Life" network growing.

"My understanding of (Linden Lab's) back-end requirements are thatthey're absurd and unsustainable," said Daniel James, CEO of ThreeRings, publisher of the online game "Puzzle Pirates." "They have(about) as many peak simultaneous players as we do, and we're doing iton four CPUs."

But Linden Lab executives have a message for worrywarts: Relax.

"It works just like Google, where each (server) is a single, cheap(server) that basically operates and is automatically deployed by oursystems and simulates the systems," said Linden Lab CEO Philip Rosedale.

Rosedale argued that his company's architecture mirrors that of theInternet itself, which he characterized as millions of servers runningin a decentralized system.

Linden Lab is constantly adding new servers as its user base grows andas users demand new "land." And since "sims" generate a minimum of $200in monthly land-use fees, Rosedale contended that the large number ofservers pay for themselves.

"Can it scale indefinitely? Absolutely," Rosedale said. "It can scaleto infinity. The underlying architecture of the Internet and of 'SecondLife' is perfectly scalable."

He said that most massively multiplayer online games, like "World ofWarcraft" and "EverQuest II," are designed around a central databasethat does the heavy lifting of managing as many concurrent users perserver as possible.

By comparison, the "Second Life" environment is spread across its manyservers, which Rosedale said are in a "tiled network" whose demands onthe central database are akin to that of e-mail.

"We just throw new machines at it all the time," he said. "So it is we who have the scalable architecture."

While there may be questions in the online-games community about LindenLab's server strategy, the model has proven successful for othercompanies.

"It works pretty well for Google and Yahoo," said Gordon Haff, a senioranalyst at Illuminata who was not familiar with Linden Lab'sarchitecture.

'Radically different' approach
"It sounds like an approach where they can segment the tasks bysegmenting the data structure," added Dan Kusnetzky, formerly the vicepresident of systems software research for IDC who is now executivevice president of marketing at Open-Xchange. "And that sounds like agood tradeoff."

Kusnetzky agreed with Haff that other companies have succeeded with Linden Lab's model.

"You can get some unbelievable scalability stories if you can thinkthrough the stories and build a lightweight architecture," he said."That's how Google and Yahoo do it."

In any case, some say "Second Life" is already bigger than they ever expected.

"They're succeeding because of their radically different approach tothis business," said Edward Castronova, an expert on virtual worlds andan associate professor of telecommunications at Indiana University.

Indeed, while most online games make money by charging every user amonthly fee, "Second Life" is free to play unless a user wants to ownland. Linden Lab makes its money off of land-use fees, the sale of itsvirtual currency and monthly fees paid by land owners.

Rosedale said Linden Lab isn't yet profitable, but soon will be.

He also acknowledged that "Second Life" has a difficult user interfacethat is an impediment to massive adoption and that Linden Lab has towork on that. He pointed to potential future plans to let users createtheir own "skins" for the interface, a step that would give controlover the interface, like all other "Second Life" content, to users.

Castronova, who said he does have some worries about the "Second Life"business model, said it's worth sticking around to find out whathappens.

"Regarding (their) business model, I have the anxiety of someone whowent out to explore a river," he said, "and I'm already 200 milesfurther than I ever thought I would get and there's still more river.Scary, but I have to keep going."