Original URL: https://www.theregister.co.uk/2011/08/11/esb_web_outage/
Amazon web outage not caused by lightning
Energy supplier questions web firm claims
Dublin-based energy supplier ESB Networks has dismissed Amazon's claim that a bolt of lightning caused the chain of events that led to its web outage last weekend.
The US giant today entered the sixth day of trying to resolve issues created by the crash at its Dublin data centre. First it blamed a lightning striking on a transformer, which it had claimed then resulted in an explosion and fire which took out power supply and backup generators.
Not so, according to ESB Networks, which confirmed that 100 customers lost electricity supply due to the failure of a 110kV transformer at the CityWest substation, but lightning was not at fault.
"The cause of this failure is still being investigated at this time but our initial assessment of lightning as the cause has now been ruled out," a spokesman at ESB told El Reg.
He said the initial supply disruption lasted for roughly one hour but admitted there was an "ongoing partial outage in the area until 11pm".
"The interruption affected about 100 customers in the CityWest area, including Amazon and a number of other data centres. Another Amazon data centre served by ESB in South County Dublin was not directly affected by the outage, though it did experience a voltage dip which lasted for less than one second.
"The fault resulted in loss of supply to 100 customers including a number of data centres who in turn have a number of third-party clients. All customers had electricity available either from the mains supply or via standby generation within one hour and mains supply was restored to all by 11pm."
Amazon's Elastic Cloud Compute (EC2) service and Relational Database Service (RDS) were out of action for seven hours from Sunday, but it said a software bug it discovered has caused additional problems.
The Amazon Web Services Service Health Dashboard today showed Amazon was still creating recovery snapshots for the minority of customers still affected by debacle.
Amazon was unavailable for comment at the time of writing. ®