Time stood still for a second on Saturday, June 30 2012, as the official global clock was adjusted to better align time with the Earth’s rotation. This “ leap second ” temporarily brought down many big-name websites and even some software platforms as they struggled to adjust to the time change.
According to Buzzfeed, Reddit, FourSquare, Yelp, LinkedIn, Gawker, StumbleUpon, and many other sites experienced outages at 23:59:59 GMT.
Amazon’s cloud server also experienced problems , some speculate due to a huge storm that took down Amazon's Elastic ComputeCloud, which hosts Netflix, Instagram, Pinterest, and more.
An executive at DataStax—a company that manages the open source Cassandra database—claims Linux did it "Initial reporting often fingered Java or even Cassandra as the culprit ... but the actual problem was a kind of livelock in the Linux system calls responsible for timers," said Jonathan Ellis, DataStax CTO and Cassandra creator in a blog post .
After experiencing problems in 2008, Google appears to be one of the few large Internet organizations to be prepped and ready for the leap second bug with a workaround they call the leap smear.
"The solution we came up with came to be known as the 'leap smear,'" Google engineer Christopher Pascoe said.
We modified our internal NTP servers to gradually add a couple of milliseconds to every update ... Google engineers developing code don't have to worry about leap seconds."