If you're new to Second Life you might not know that you're in "the future of the internet" according to no less a person than Phillip Linden. I remember these sorts of statements from my early days in SL, but this one is cited in an article written in the dim distant days of last December, so it looks like Phillip's dream is still alive.

There is nothing wrong with having a dream of course, nor aspirational targets. In fact it's great that Phillip still does. But sometimes you have to bed your dreams and targets in reality. What we are noticing in SL at the moment is growing pains. We don't call them that, rather we swear when logins fail, teleports fail, clothes vanish and become "Missing Image", our L$ balance vanishes, the new toy/dress we've just bought doesn't get delivered, friends online falls over, search breaks and so forth. It seems that Saturday and Sunday evenings GMT, lunchtime SL Time, are the times that these things happen. Not once or twice, but week after week after week.

The underlying cause(s) of these issues seem to be directly linked to concurrency: how many of us eager residents are exploring our second lives at the same time. The actual bottleneck is not directly our fault, it is more that an internal query becomes the new bottleneck.

Some of the bottlenecks are simply linear. I suspect search falls into that category. At any given moment some proportion of us are using search. Say it's 10%: when there were 5,000 of us on the system had to cope with 500 queries at once. When there are 20,000 on it's coping with 2,000 at once. Whatever the patch most recently applied seems to have fixed it, but lets say it makes the query run twice as efficiently: when the population doubles again we'll hit the next problem. This may not be entirely true, as the population grows the size of the database of things that can be searched also grows and may well affect the durability of the patch, but it's close enough to make the point clearly.

Pipeline problems are worse. If I'm standing in an empty sim there's some load on the sim to download images, but it's basically all for downloading me. Add a second person and the part of the load for avatars doubles, to each of two people, so it is four times more. Add a third and it's three times as much to each of the three, or nine times the load. The load squares each time. If we add some content the load for this is higher too: there is, unless we're somewhere with lots of building going on, a stable load, but it is streamed to each client afresh, so that rises roughly linearly. Not entirely at first, because we're probably looking at each other, so the views from my friends are new compared to what I'm seeing and may have to be loaded for the first time.

We've seen places like geocities sites, and more urgently (to scripters) and relevantly to SL the lslwiki exceed the download quota, which is the current internet equivalent to SL's concurrency issues. But if SL is really going to become the new internet, it needs to have the stability to cope with the kind of load that google handles daily. That's millions of users at once. Google might handle things very differently than SL, but if SL is going to be the future of the internet, it has to cope with what the internet is used for already, doesn't it?

Are we on course for getting there, or will the challenges prove too much?

EDIT: As of 3:04 pm Second Life Time there is a new contingency plan announced which MAY be run if the grid issues related to concurrency continue. Read about it on the official blog.