Some customers of Amazon's EC2 cloud computing service were offline for more than four hours Wednesday night after an electrical storm damaged power equipment at one of the company's data centers. The problems began at about 6:30 pm Pacific time, and most affected customers were back online by 11 p.m., according to Amazon's status dashboard. The company said the outage was limited to customers in one of Amazon's four availability zones in the U.S.
"A lightning storm caused damage to a single Power Distribution Unit (PDU) in a single Availability Zone, the company reported. "While most instances were unaffected, a set of racks does not currently have power, so the instances on those racks are down. We have technicians on site, and we are working to replace the affected PDU."