11.07.2014: An update on performance improvements and adjustments is available here.

Second Life was originally designed for nearly all data and Viewer interactions to go through the Simulator server. That is, the Viewer would talk almost exclusively to the specific server hosting the region the Resident was in. This architecture had the advantage of giving a single point of control for any session. It also had the disadvantage of making it difficult to address region resource problems or otherwise scale out busy areas.

Over the years we’ve implemented techniques to get around these problems, but one pain point proved difficult to fix: asset delivery, specifically textures and meshes. Recently we implemented the ability to move texture and mesh traffic off the simulator server onto a Content Delivery Network (CDN), dramatically improving download times for Residents while significantly reducing the load on busy servers.

Download times for textures and meshes have been reduced by more than 50% on average, but outside of North America those the improvements are even more dramatic. That is great news, but the most amazing improvement has been on the simulator servers themselves. The following chart graphs servers on a production release-candidate channel with high HTTP load conditions before and after we rolled the CDN code onto them:

The high load conditions almost completely disappeared! We knew that we would get a major drop in load with the move, but this blew us away. At first we didn’t believe it and spent two days trying to figure out what we did wrong. There was nothing wrong; this was real.

The results of all of this are faster scene loads, quicker object rezzing, far fewer problems with fuzzy or cloudy avatars, fewer teleport failures, and more! The feedback from Residents has been fantastic. We’re loving it, too! Everything is just so much snappier.

We have finished rolling the CDN code out to the grid, and the results have remained extraordinary. This week, we are also fully releasing our HTTP Project Viewer, which will make the CDN change even better by taking advantage of the elimination of server-side rate limiting. We have been extremely happy with the results so far (psst, we’re talking an 80% reduction in content download times).The CDN benefits are available to everyone regardless of which Viewer you choose to use. All users of the official Viewer will also be able to enjoy the results of the HTTP improvements, and third party developers are able to adopt these changes in their Viewers as well.

We are very happy to be finally releasing these improvements to everyone. Give it a try and let us know what you think!