Evan Schuman's StorefrontBacktalk

When Amazon.com has server problems, it shares them with other key retail players, including Target.com and Borders.com. At least that’s the E-Commerce lesson those three retailers?and perhaps others?are learning this week.

All three retailers began seeing a sharp drop in server response times starting Wed., at about 9 AM, according to sources familiar with their servers. The three are connected because, to varying degrees, Amazon is hosting chunks of the E-Commerce sites of both Borders and Target.

How sharp a drop in server performance? Amazon’s uptime is typically one of the best, hovering between 98 percent and 99 percent, the sources said. Starting Sept. 20 at about 9 AM, it plummeted into the 80s and by the night of Sept. 21, it had dropped to 73 percent and by the morning of Sept. 22, it had dropped to 60 percent. The drop in response time for Borders and Target fit “the exact same pattern,” starting at the same time and increasing and decreasing at the same rate, one source who examined the data said.

Borders, which is tightly tied into Amazon’s operations, dropped as low as 75 percent, one source said, while Target fared better, dropping only as low as about 85 percent.

An official with traffic monitoring firm Keynote Systems on Friday morning reported that their logs showed the identical server response slowdown pattern, but added that it appeared to stop at about 4:30 AM Friday.

Ben Rushlo, Keynote’s senior manager of professional services, said that Keynote’s logs (see those logs here) showed not only the Amazon server problems but showed how they perfectly matched the slowdowns with both Borders and Target.

Further establishing the connection is that Amazon, Borders and Target “all went back to normal at the exact same time.” All sites returned to server performance approaching 100 percent at about 4:30 AM Friday, Rushlo said. According to Keynote’s logs, Amazon overnight had dropped down to 60 percent server response.

The server problems appeared to be national and the time-out errors most often were impacting Amazon’s prized homepage, suggesting “some serious problems” possibly involving a hardware repair effort that didn’t quite fix a problem.

There were a handful of reports of Amazon’s site not loading on Sept. 19, suggesting that the problem might have started then.

Officials at Amazon, Borders and Target did not respond to requests for information about their server status.

This apparent server problem raises some concerns as the industry heads into the intense holiday shopping season. First, this is the second report of an Amazon outage in a month. Secondly, the fact that Amazon is also housing the E-Commerce guts for other sites?such as Borders and Target?making a crash or a server slowdown at Amazon ripple through the rest of the industry.

This is also not coming at a good time for Target.com, which is also fending off bad publicity from its legal battle against visually-challenged consumers.

The fact that last month’s Amazon outage occurred on Aug. 21, which is exactly?to the day?when this slowdown occurred raises the possibility that the events might be tied into some calendar event at Amazon, such as a schedule for release or patch updates.

Neither Borders nor Target responded to requests to comment for this story. Amazon.com’s director of corporate communications, Patty Smith, E-mailed Friday afternoon but only said she had “not heard of any problems with our servers.”