Earlier today, the over 140 million users of Twitter found that for the better part of an hour today, the service simply was not working. This was the second time in about five weeks that Twitter had suffered a system wide extended outage. It got hit with a few hours of downtime in late June. After its systems were repaired, Twitter said the issue was due to "a cascaded bug in one of our infrastructure components."
So what happened today? In a post on its official blog, Twitter's vice president of engineering Mazen Rawashdeh stated:
The cause of today’s outage came from within our data centers. Data centers are designed to be redundant: when one system fails (as everything does at one time or another), a parallel system takes over. What was noteworthy about today’s outage was the coincidental failure of two parallel systems at nearly the same time.
Rawashdeh called the issue an "infrastructural double-whammy" which we assume is a highly technical and little used term. He apologized for the downtime and added, "We are investing aggressively in our systems to avoid this situation in the future." It will be interesting to see how Twitter holds up during the next two weeks, when the 2012 Olympics in London will be front and center on social networking sites.
Source: Twitter blog