Twitter’s an Energy Guzzler & Other Hard Truths for Web 2.0 App Addicts
For most Twitterers, it’s safe to say that the environmental impact of tweeting what you had for dinner ranks quite below top of mind. But web applications that involve constant updates and real-time information — such as many of those on the Twitter platform and especially those supported for mobile — are like the Hummers of web apps, guzzling away energy through continuous server connections for each user.
That’s according to Greg Smith, director of product marketing for Citrix System’s application networking division. On Tuesday, the company announced a new feature for its Netscaler lineup (designed to speed delivery of web applications for use across the wide area network) that could help shrink the server needs — and thus the energy consumption — of those Hummer-like and highly addictive apps.
Here’s the thing with rich, interactive applications: Each user typically maintains long-lived, or continuous connection with the server. In traditional, more static web pages you would click on a link, and that would request information from the server. The server would give you that information, then close the connection. At any one time, Smith said, only some 5 percent of online users would be connecting with the server.
By contrast, in something like an auction site, a multiplayer game or an energy-monitoring console for the smart grid, it’s closer to 100 percent at any given time, and web 2.0 businesses need to keep that much more server capacity on tap to accommodate peak demand. Users generally keep an open connection with the server in order to get a constant stream of updates, even if the same information (such as your latest tweet or the most current bid) is going to multiple users. When these applications go mobile, users tend to stay connected for longer periods of time — updating and checking Twitter around the clock on an iPhone for example, rather than signing out when not at a computer.
As ChannelWeb points out, we’re also subscribing to more newsfeeds and sites that constantly “push” information without us actually clicking on anything. All of this leads to “server sprawl,” with businesses needing to maintain a huge amount of processing capacity, ready to connect with tens or hundreds of thousands of users at any given time.
What Citrix is doing now with Netscaler (a web acceleration business acquired in 2005), Smith said, is adding technology to push data to thousands of users concurrently with a system that operates in front of the backend servers. Servers can send content one time to Netscaler, which will then “broadcast it out,” Smith said, removing the responsibility of the less-efficient server infrastructure to manage individual connections — and slashing server costs for delivering Web 2.0 applications by as much as 20 percent by reducing power consumption, cooling needs and operating expenses.
So the good news: We don’t have to kick our app habits to tame sprawling servers.
The trade-off between constant connectivity and resource usage has always been part of system design – as have various techniques for optimising the use and re-use of the available connections …
… but Twitter itself doesn’t use constant connections, or a dedicated connectoin per-user – it requires users to poll the service regularly through a standard HTTP connection (i.e. so Twitter’s servers heavily re-use their connections between users) – and indeed limits the number of times each user is able to poll. This strikes me as a pretty sensible compromise between delivering value and using resources … and not at all wasteful enough of resources to justify the Hummer analogy – for Twitter at least.
Maybe Citrix should focusing on making their core product not suck as bad as it does.
I found your blog on Google. I’ve bookmarked it and will watch out for your next blog post.
what do you think of twitter?