Original URL: http://www.theregister.co.uk/2011/08/12/amazon_ebs_investigation/

Amazon web services back up and running

But reasons for outage still being investigated

By Paul Kunert

Posted in Cloud, 12th August 2011 09:57 GMT

Amazon has finally resolved the lingering issues from the outage last weekend, but the root cause of the power failure has yet to be determined by energy provider ESB Networks.

The web giant said at the time that lightning had struck a transformer in Dublin on Sunday, which knocked out all power provision including the back-up generator.

But exploration of the problem by ESB ruled this out, a spokesman at the Irish firm told The Register.

"Investigations are ongoing but we still don't know the official cause," said the ESB man. "We know that it was a transformer fault, a transformer blew."

He said it was not dismissing Amazon's claims of lightning, as reported yesterday, which the web player made on its services health dashboard hours after the incident.

At 3.01pm PDT Amazon said: "We understand at this point that a lightning strike hit a transformer from a utility provider to one of our Availability Zones in Dublin, sparking an explosion and fire."

A spokeswoman at Amazon said ESB had made the "initial assessment that the cause of the power outage was lightning. Amazon and ESB have been on close contact to understand the root cause of the power event in question".

She added: "As often occurs during investigations like this, root cause is not always what it first appears to be."

The firm is reporting that web services are operating normally today. ®