Gmail Down? Outage Spreads Confusion

Sept. 2, 2009 — -- It only lasted for an hour and a half, but yesterday's Gmail outage was an online hiccup felt 'round the world.

Gmail, the popular e-mail service offered by Google, went down for a "majority" of users yesterday. By late afternoon, eastern time, the company said, "We've fixed the issue, and Gmail should be back up and running as usual."

Google said it made a mistake during some routine system maintenance, and apologized profusely: "Today's outage was a Big Deal, and we're treating it as such," said Ben Treynor, a Google vice president who is Site Reliability Czar (yes, Googlers have titles like that).

What happened? "We took a small fraction of Gmail's servers offline to perform routine upgrades," wrote Treynor in an explanation on Google's Gmail blog, which the company e-mailed to ABCNews.com. "This isn't in itself a problem -- we do this all the time, and Gmail's web interface runs in many locations and just sends traffic to other locations when one is offline.

"However, as we now know, we had slightly underestimated the load which some recent changes (ironically, some designed to improve service availability) placed on the request routers -- servers which direct web queries to the appropriate Gmail server for response. At about 12:30 pm Pacific a few of the request routers became overloaded and in effect told the rest of the system 'stop sending us traffic, we're too slow!'."

From there it was a cascade effect, and pretty soon most of the system was down.

Outages of online e-mail services are common -- the market leaders, Yahoo, Microsoft's Hotmail, AOL and others have all had their headaches this year -- but it is rare for such problems to be widespread.

Gmail is the third-most-popular e-mail service in the United States; only Yahoo and Hotmail have more users.

The service is free, but Google increasingly has been marketing its online services, such as e-mail and word processing, to business users.

People who use "clients" -- e-mail programs in their own computers that take the place of the Gmail Web site -- had no problem. Google provides instructions on how to set up a client program; some, such as Microsoft Outlook or Yahoo's Zimbra Desktop. Some, such as Zimbra, are free.