Yesterday Twitter was down for everyone around the world. Users were unable to connect to Twitter to read or leave messages and according to The social network, mobile clients were not showing tweets. Twitter says that it immediately began to investigate the outage after it was discovered at 9 AM PDT.
The investigation determined that there was a cascading bug in one of the infrastructure components that occurred after an update. A post on the official twitter blog reads:
We immediately began to investigate the issue and found that there was a cascading bug in one of our infrastructure components. This wasn’t due to a hack or our new office or Euro 2012 or GIF avatars, as some have speculated today. A “cascading bug” is a bug with an effect that isn’t confined to a particular software element, but rather its effect “cascades” into other elements as well.
Some speculation pointed to hacks or other new elements that may have caused the outage. Twitter says its corrective action was to roll back to a previous, stable version. The recovery began at about 10:10 AM PDT.
Twitter also takes the time to point out that despite the worldwide outage this week, for the past six months twitter has been at least 99.96% stable and often is much is 99.99% stable. Twitter says that in real world terms that percentage means during an average 24-hour period, it was up and stable to everyone roughly 23 hours, 59 minutes, and 40 seconds.
