Tony Walsh has, as others do, some doubts about whether Second Life is sustainable as a business. But he also poses another question that I hadn’t come across before: “Is Second Life sustainable ecologically?”
He quotes Philip Rosedale, the head of Linden Lab, the company behind the virtual world: “We’re running at full power all the time, so we consume an enormous amount of electrical power in co-location facilities [where they house their 4,000 server computers] … We’re running out of power for the square feet of rack space that we’ve got machines in. We can’t for example use [blade] servers right now because they would simply require more electricity than you could get for the floor space they occupy.”
Walsh notes that on average there are between 10,000 and 15,000 avatars in Second Life at any given time, a number that’s growing rapidly. He wonders: “How much power do 15,000 human beings consume daily compared to 15,000 avatars?” Hmm. That’s an interesting question.
So let’s do the math.
If there are on average between 10,000 and 15,000 avatars “living” in Second Life at any point, that means the world has a population of about 12,500. Supporting those 12,500 avatars requires 4,000 servers as well as the 12,500 PCs the avatars’ physical alter egos are using. Conservatively, a PC consumes 120 watts and a server consumes 200 watts. Throw in another 50 watts per server for data-center air conditioning. So, on a daily basis, overall Second Life power consumption equals:
(4,000 x 250 x 24) + (12,500 x 120 x 24) = 60,000,000 watt-hours or 60,000 kilowatt-hours
Per capita, that’s:
60,000 / 12,500 = 4.8 kWh
Which, annualized, gives us 1,752 kWh. So an avatar consumes 1,752 kWh per year. By comparison, the average human, on a worldwide basis, consumes 2,436 kWh per year. So there you have it: an avatar consumes a bit less energy than a real person, though they’re in the same ballpark.
Now, if we limit the comparison to developed countries, where per-capita energy consumption is 7,702 kWh a year, the avatars appear considerably less energy hungry than the humans. But if we look at developing countries, where per-capita consumption is 1,015 kWh, we find that avatars burn through considerably more electricity than people do.
More narrowly still, the average citizen of Brazil consumes 1,884 kWh, which, given the fact that my avatar estimate was rough and conservative, means that your average Second Life avatar consumes about as much electricity as your average Brazilian.
Which means, in turn, that avatars aren’t quite as intangible as they seem. They don’t have bodies, but they do leave footprints.
UPDATE: In a comment on this post, Sun’s Dave Douglas takes the calculations another step, translating electricity consumption into CO2 emissions. (Carbon dioxide, he notes, “is the most prevalent greenhouse gas from the production of electricity.”) He writes: “looking at CO2 production, 1,752 kWH/year per avatar is about 1.17 tons of CO2. That’s the equivalent of driving an SUV around 2,300 miles (or a Prius around 4,000).”
Cory,
Can I assume you work for Linden Lab, as Tony implies? If so, thanks very much for the clarifying data.
Note that, in addition to the podcast Tony mentions, Philip Rosedale said, in a Financial Times interview a couple of days ago: “It’s hard to scale the physical infrastructure much faster than 40 or 50 per cent a month. We have more than 4,000 servers now, so to deploy 2,000 servers a month would be difficult and we will have challenges meeting that.”
Assuming Cory’s numbers are accurate, we need a new point of comparison. The average Bolivian uses about 500 kWh a year. So we can now say, roughly, that “Avatars consume as much electricity as two Bolivians.”
Nick
WTF!!?? WHAT THE HELL IS AN AVATAR???
An avatar is a person’s on-line alter ego. Your avatar on this blog, for instance, is the name I_PWN_NOOBS. On Second Life, people’s avatars take the form of computer-generated figures.
ok thanks.
ps I PWN J00
Nick, I understand that you can divide annualized numbers by 24*365 to arrive at hourly numbers. Don’t know why you would assume otherwise.
I am not arguing about the math – but about the relevance of the comparison.
It seems to me you’re trying to make a statement about the increasing density of computation in the industrialized world and consequently the increased energy footprint of IT. Clearly it matters for that discussion what the actual density of computation is and for that “per avatar” is irrelevant whereas “per active player” is not.
I just find it less interesting what the power consumption WOULD be if the density was 1 is all I’m trying to say.
The SUV example appended to the end of the post illustrates the case. Driving 2,3000 miles in an SUV is perfectly plausible, maybe even low, for a typical car owner. So it’s interesting to know that just commuting to work pollutes as much as doing everything else you do to stay alive in Brazil.
So drivers consume MUCH more energy than Brazilians – and since the point of frozen burritos is to reduce food preparation time, burrito eaters probably do too.
I think the PC energy usage is at the lower end of the scale.
Mine draws 400W at the maximimum and from what i can tell regularly does, high end PC’s will use in excess of 800W.
I wonder if theres a WoW carbon neutral charity out there somewhere, my /played * energy usage would be slightly scary I’m guessing
You’re welcome. LOL, yes I work for Linden Lab, although Google likely answers that faster than I. No worries on the mistake, there is a lack of precision in the use of “simulator”, “region”, etc, which often leads to confusion, even among Linden Lab employees. Initially we did run 1 to 1, but as mips/watt improved we have been able to run at higher densities. Right now, we are on dual, dual-core Woodcrest Xeons because they maximize mips/watt. We’ll see if AMD recaptures the crown as their die shrink rolls out.
If we really want to think about this, we’d need to roll in the various databases, asset servers, web servers, and other machines that go into keep SL up and running. We have around 1500 physical machines. But we are nowhere near maximizing the capacity of the grid machines, so as we continue to improve scaling issues, we will see at least 2 to 3X the current avatar densities ove the entire grid. But, as already noted, these numbers are dominated by home PCs.
Finally, if you are really going to do this calculation, you should really be comparing it to what you can do in SL, which is a lot more than avatars just running around. Anywhere SL goes you have markets — to the tune of US$3.5 million a month exchanged for US$ — as well as education, jobs, etc. Think about China, for example. 1% of China is urbanizing a year, so that’s 13 million people a year moving into the equivalent of 2 new New York Cities a year, seeking jobs, education, and opportunties. If you could instead take broadband, power, and computers to the rural areas — carrying SL and markets with them — how much power would you save? Or, if doing business collaboration in SL allows you to save 5% of your travel budget, how much energy do you save in giving up 1 flight in 20? The full carbon picture is where the interesting questions are. How do virtual worlds allow you to dodge traditional geographic limitations?
Cory, Interesting points. Thanks. Nick
Cory, where do you suppose the BBC got this information from: “[Second Life] runs on 4,100 computers housed in two server farms – one in San Francisco and the other in Dallas.”
How did they come up with 4,100 servers when you are only running 1,500?
I particularly enjoyed this passage, describing Linden Lab’s headquarters, from that BBC article: “In a large, airy open plan office generously decked out with pot plants and figurines of characters from various sci-fi movies, around thirty people sat at their computers keeping an eye on their digital world.”
Generously decked out with pot plants?
That seems a little risky, even if it spurs creative thinking on the part of the staff.
I believe Gareth is referring to “potted” plants – despite SF’s well-earned reputation for counter-culture and underground comix, the work hard, play hard mentality here at the office rarely extends past the use of a good 25-year old bourbon. For those looking for more of a rush during the day, the kitchen at Linden Lab is stocked with M&Ms and energy drinks.
Tony, as Cory pointed out, our active cpu count is sometimes mistaken for our “server” count. We have a variety of machines in use, some dual core Opertons and some newer dual, dual core Xeons. We run a “region” of 16 acres of land on a single CPU, or 4 such regions on a 1U Woodcrest server. We’re adding new racks every week, so the numbers change before they appear in print, but the 1500 number is the “server” count, 4100 is the “cpu” count.
(We do some other multiplexing with “void” simulators that are meant to provide physics and connective tissue to other land, so the math above can’t be taken too literally.)
I think this is a fascinating discussion. I computed at ecoiron that an average human beings runs at 100 watts, and based on current energy consumption, has about 100 energy slaves (the equivalent of one human) working for them on a daily basis.
(http://ecoiron.blogspot.com/2006/08/do-my-bidding.html)
Second Life seems to be another, almost literally, energy slave that people employ for fun, profit, etc. The interesting part for me is the hierarchy of energy needs e.g. do you keep your toaster slave or your Second Life slave? Rich countries haven’t had to make these decisions yet; poor countries have been making them for decades. As the energy crisis heats up, it will be interesting to see what survives.
Just a quick note… there are very few apps that get my fan going on my macbook. When I run SL it runs non-stop. Also, battery life (when I’m foolish enough to run SL on battery alone) drops to less than 30 minutes. There is significant marginal energy use at my end for running SL that comes from the computing intensive nature of the environment.
Why the focus on Second Life?
It seems to me that Linden Lab’s servers are unremarkable; they just happen to be hosting Second Life.
The environmental implication of this discussion seems to be that we should be calculating the energy use of using any given user accessing any given server on the Internet.
… and therefore the question Nick started with becomes a more worrying one: “Is the Internet sustainable ecologically”?
I keep coming back to this topic for some reason…
From what I can gather anecdotally about SL they have virtual regions, or sims, tied to physical hardware. From what they say on their blogs etc. it doesn’t seem that they have a virtualization infrastructure in place yet. Give that many regions have absolutely nothing going on while others may have as many as 100 avatars present at a time, the electric cost per av ends up inflated (because of all the idling processors).
A smart virtualization strategy that combines low-load sim virtual machines onto a common physical hardware platform, while isolating the high-load sims to a dedicated physical platform could probably greatly reduce the number of physical machines they would have to deal with. The most difficult technical challenge would be migrating a sim whose traffic is increasing to a more dedicated physical platform in-flight without disrupting the game.. and that might be really hard.
Short of dealing with that technical challenge, they might combine virtual machines for historically low load sims onto a single physical server. They could couple this to a scaling land rent fee since these regions would now be less able to take on high av load.
Given their well-publicized use of S3 already, I wonder if they aren’t thinking about how they might use EC2 for something like this once it comes out of beta. Switching to EC2 without changing the 1-to-1 relationship between sims and machines though would probably not be cost effective.
Well, from what I’ve been reading around the blogs etc this week, the sim servers look after more than just the lanscape and avatars on them- all the uploads, assets etc are scattered around on them in some kind of way nobody outside of LL (and maybe few inside :D ) know about. So these servers are maybe already doing work even when apparently idle, I don’t know. Maybe an explanation (if it’s not a trade secret) would be handy? Possibly off topic for a discussion purely about power consumption except to say “our servers are rarely idle in any sense because of X and Y”.
energy usage is one factor. what about the kind of energy? iceland has clean, geothermal energy; so much that it’s cheaper to bring bauxite from australia and process it into aluminum there. what if the energy being used were clean, was no outputting co2?
To start I think it very important for everyone to think of the effects of our choices.
Ok lets start with city design and development. They keep getting bigger without much regard for what that means. There is the concept of arcology which addresses this. Take the automobile out of the city. I do not know how to make the comparison of my car to my computer, but if I include all the factors I bet the car is more costly in terms of resource usage and pollution. So if i can do more business online great. If i make a city where walking is actually feasible even better cause I could use the excercise. But of course I’ve been wanting to hook up a stationary bike to my computer so I can kill 2 birds with one stone, excerise and electricity. And the production of concrete is one of the greatest contributors to greenhouse gases along side electricity and automobile.
So there are many sources for our energy needs. And research is continuing into more. The worlds first full-scale fusion reactor is being built in france, due to be up and running around 2016. Hopefully it’ll break even. But there are other concepts at least as promising, so perhaps in 25 years we’ll have that as a source for electricity. That would take care of alot of our concerns. But we aint there yet, and they are costly.
And even if we didn’t have something like Second life or any others, all our businesses use massive computer resources. And as for the internet being sustianable and what would we choose (toaster, mircowave, etc, or computer) the internet is one of the greatest inventions the humans species has created, its potential is much greater than most people consider I suspect. Is it not worth it?
BTW I do not have an account on Second Life, or any other virtual world.
cheers all
I think the issue is bigger than SL. We should be able to choose ecologically responsible internet connections no? Online and in real time too.
I tried out SL. The wow factor for experiencing a controllable avatar was very big but, it can be slow, or crash. One night, after a friend with more SL *age & experience* showed me some of the adult entertainments within SL, I was motivated to check out more of that world. I made the mistake of making a one-line comment to a particularly buff male avatar–“hey stud”–just to see what would happen. He made no reply. Within a minute after parting, my avatar’s legs kept collapsing.
I know that’s not especially relevant to the environmental discussion of SL happening here (which I’ve already forwarded to my friend), but I needed to share that. Not to alarm anyone, but apparently, you can ‘catch’ something in SL.
On a more related note, this site details how energy could be saved if webpages were designed with darker backgrounds. Read about it: http://www.risingphoenixdesign.com/blackback.html
My group uses SL for international meetings so the overhead – much lower than first claimed – is far less than people flying in for a face-to-face meeting.
Ironically, we have a meeting on Sunday about climate change. Details at
http://luzoorbit.blogspot.com/
Please forgive me for being horribly late to the discussion. I just got pointed to this arcticle by someone asking me, how I could “justify evangelizing Second Life, even though this will destroy the climate”. So I checked it out.
Summary (and please forgive me): Nice Headline, misleading math.
As Cory pointed out the equation “1 simulator = 1 server machine” is wrong – but thats not your fault; most articles on this topic do not use very precise wording. The equation is “1 simulator = less than 1 CPU”. Most servers at the Linden Lab colo sport 2 – 4 CPUs these days.
So now (May 2007), we are probably talking about max 2,000 servers (= boxes).
What is more problematic in this calculattion is the fact that you are using “concurrent users = avatars”. Sound plausible, but is misleading.
Currently, the Linden Lab grid is used by some 1,000,000 avatars (regular users). They are not allways online, of course. This does not change the fact, that this is the “population” of Second Life (when counting the population of a country you are taking into account sleeping people, too, don’t you?) 1,000,000 avatars are sharing the cost involved with the day to day operations of the Second Life grid.
On the other hand, those servers probably consume more in the area of 500 Watts and a PC running Second Life need at least 250 Watts.
The avarage concurrency these days is around 30,000.
So we have
2,000 servers * 500 Watt * 24 * 365 +
30,000 clients * 250 Watt * 24 * 365
= 74,460,000 kWh per year
So the cost (energy wise) to support one avatar in Second Life for one year is more in the ball park of 75 kWh these days – and not 1750 kWh.
This is still a substantial amount of energy. But nowhere near the energy consumption of a resident of one of the earth’s poorest countries.
Actually it is less energy than is needed to drive an avarage US-made automobile 100 miles.
Markus,
As noted above, this is a purely illustrative calculation of the energy required to keep an avatar “alive” for a 24-hour period in order to make a comparison with the energy consumption of a person over a 24-hour period. For that reason, I use the “average population” of Second Life as a proxy for the population of an actual country or region. There are, of course, other ways to calculate SL energy use, and I would encourage you and others to explore them all.
Nick