More Twitter Downtime Likely

Twitter was offline for seven hours to complete a data center move.

Few widely-used web services can go offline for more than six hours without customer conniptions. Twitter proved itself the exception this morning when planned maintenance extended past its four-hour window, leaving the service offline for about seven hours. It was the latest in a series of outages for Twitter, a free service that lets users stay "hyper-connected" with short posts about what they're doing, with a limit of 140 characters.

Twitter recently switched data centers, and related maintenance Saturday was expected to leave the service unavailable for 12 hours. "What other basic form of communication goes down for 12 hours at a time?" wondered Dave Winer, who nonetheless was forgiving about Twitter's need to upgrade. The Twitter blog later reported that it was able to do much of the work without taking the service completely offline. But only for the moment.

Twitter still needed to copy its main database over to the new data center, which would require at least four hours of downtime, according to an advisory on the Twitter blog. That outage extended to seven hours before service returned. While some commenters complained, others were magnanimous:

You provide a free service. So take all the downtime you need. ... It's really funny to me how some people think you guys at twitter owe them uptime for some reason.

Twitter apparently won't pursue an "uptime optional" policy just yet, but there's probably more downtime ahead, as the Twitter blog reported at midday. The company said the extended outage this morning was due to "our largest and most complex maintenance project" ever:

Everything went pretty much according to plan except for one thing: an incorrect switch. The switch in question caps traffic an unacceptable level. In order to correct this, we'll need to get some hardware installed. Unfortunately, that means we're not done with our datacenter move just yet. This type of work can be frustrating but it's all towards Twitter's highest goal: reliability.

For now, Twitter seems to have enough goodwill among its user base to survive these growing pains, as noted by Adam Ostrow at Mashable. "It seems no matter how unreliable or frustrating Twitter can be with its downtime, users flock back to the site," Adam observes. "In fact, for the brief moments I was able to access it this morning, the main topic of conversation was jubilation over the return of Twitter from its maintenance."