By Laura Isensee
A majority of Google users from California to Taiwan found themselves without access to Google’s popular email service on Tuesday.
The company outlined what went wrong on its blog.
“We took a small fraction of Gmail’s servers offline to perform routine upgrades,” Ben Treynor, vice president of engineering and site reliability czar, wrote.
But the company “slightly underestimated” the load that placed on other servers — called request routers — that direct web queries to the right Gmail server for response.
So those servers became overloaded, pushing the load to the remaining request routers, causing more to become overloaded. And “within minutes nearly all of the request routers were overloaded,” Treynor said.