Evan Schuman's StorefrontBacktalk

In the middle of a major Labor Day sale, Costco.com completely crashed and stayed down for three hours, from about 11 AM to 2 PM (New York time), due to an unspecified network—as opposed to volume—problem, said the chain’s E-Commerce Senior VP.

Although an outage is never a pleasant thing, this one was especially untimely for quite a few reasons. First, it was the middle of the day (or the start of the business day, depending on which coast you’re on). Second, it was in the middle of a major well-publicized sale. And the coup de grâce of this outage: It was a federal holiday, potentially meaning a skeleton crew in the office and perhaps difficulty in obtaining replacement parts.

Site monitoring firm Gomez captured the outage, and it was impressive in its completeness. Typically, outages show a sharp reduction in successful connections and then a performance drop to almost nothing, with just a few consumers able to access the site. The Costco Labor Day crash was a true crash, with the site showing excellent performance before immediately dying.

“During the timeframe we saw on the chart, the site essentially disappeared. The infrastructure itself was simply not reachable,” said Matt Poepsel, VP of performance strategies at Gomez. “We typically see sites slow down as the infrastructure [melts]. This one just fell off the cliff. To see it in the middle of the afternoon is very unusual.”

Ginny Roeglin, who as Costco’s Senior VP for E-Commerce owns the site, didn’t want to get specific about the crash’s cause, other than to say that it was “a network-related issue that required fixing” and that it had nothing to do with traffic volume.

Keynote Systems, another firm that tracks Web traffic, said although the crash was bad, it could have been worse. “This is a pretty extreme event for a major retailer like that,” said Shawn White, the firm’s director of external operations. “Thank goodness it’s not Black Friday.”

White suggested Costco might have benefited from ongoing site monitoring—so it would be alerted to a crash instantly—but there is every indication Costco already knew about the crash instantly.