This Thursday, Twitter encountered a global service down incident. This is the second service down incident since last month. Later Twitter updated its website and stated that users might not be able to access Twitter temporarily.

Twitter admitted the service down incident and explained that this time's service down was caused by problems of their both data centers.

Ok, now lets summarize the service down incidents encountered by Twitter in past few years.

in May 2008, Twitter's new engineer team was changing its service architecture in order to handle the increasing traffic. Because of the instability of the system,, some service were down and some temporary functions were lost.

In August 2008, Twitter stopped providing SMS service to users in UK. In the following 5 months, one instant message service through XMPP robot was unusable.

In October 2008, Twitter's blog said that Twitter's instant message service was not an temporary service down, it needed to be repaired.

June 12, 2009: Twitter encountered the so-called "Twitpocalypse" problem. Because each tweet corresponds to a unique digital ID, and at that time the Tweet digital ID has been close to the 32 bit maximum signed integer value (a total of 2,147,483,647 messages). Although Twitter site itself had no fault, but many third-party applications could no longer access newly published Tweets. Twitter released a patch to fix defects, but there were still some iPhone applications in the Apple App Store queued for review, so Twitter was forced to extend the time to repair.

June 25, 2009: Twitter was down in the day at least once, and the site ran slowly. During this period, records show that within an hour, more than 50,000 tweets related to the news about Michael Jackson's death, Michael Jackson was ranked seventh on the hot topics.

August 6, 2009: Twitter and Facebook were attacked by distributed denial of service attacks, Twitter was forced to be offline for several hours due to this attack. Later it was identified that this attack was targeted to a Twitter user who supported Georgia on the first anniversary of the 2008 South Ossetia War, rather than to the site itself.

September 22, 2009: the total amount of the tweet message was more than the maximum 32 bit  unsigned integer value (a total of 4,294,967,296 messages), some third-party application software once again could not work

December 17, 2009: Twitter was attacked by hackers, the site's welcome page was replaced by a green banner image, and write "This site has been hacked by Iranian Cyber Army.".

June 2010 - July 2010: during the World Cup in 2010, Twitter had a very high denial of service rate(10% -20%), service response delay also increased.

November 2010: part of the user encountered a service error, when they logged into their accounts, they saw the error page with a large whale. These accounts were not locked account, the users still could see the reply to their own message and the published content, but the timeline and other functions were abnormal.

Reference : http://news.csdn.net/a/20120727/2807820.html