Single point of failure (SPoF) sounds like an aeronautical term related to NASA's Mars mission, but it's not. It refers to problems in Web site tag management systems (TMS). TagMan, which offers a TMS solution, set out to simulate multiple failures for four major airline Web sites (Virgin Atlantic, United Airlines, U.S. Airways and JetBlue) driven by online bookings.
The tests relied on a specific method to determine whether a consumer could, theoretically, book a ticket if the site lacks a tag management system. Detecting a tag management SPoF meant diverting the TMS to a "black hole server," demonstrating what would happen to a Web site its TMS were to go down.
While one airline's Web site managed to do fairly well, three failed the test. The sites that failed could not take bookings for at least 20 seconds. The test shows Virgin Atlantic loaded correctly and allowed the ability to book flights. United Airlines produced a white page for 20 seconds until its TMS server-call timed out. JetBlue's and U.S. Airways' date pickers failed to interact when the TMS became unavailable. It didn't allow consumers to make bookings when the booking page fully loaded.
The findings show third-party content like social widgets from Facebook, Twitter and live chat are not controlled by the main Web site. Any failure to synchronize scripts or tags can disrupt the site. Sometimes it's due to a hardware failure, overload or CDN/hosting infrastructure. TagMan calls out Amazon Web Services for two failures in the past year that disrupted service for start-ups it hosted.
More than 50 U.S. Web sites tested failed the simulation, according to TagMan's white paper. Aside from airlines, it put at risk a variety of ecommerce sites like Kmart, BlueFly, Nordstrom, Sears, Tommy Hilfiger, Fox, and Fingerhut.