Amazon Web Services experienced an outage in one of the East Coast availability zones for its EC2 service early Wednesday due to power problems in a data center in northern Virginia. Failures in a power distribution unit (PDU) resulted in some servers in the data center losing power for about 45 minutes. It took several more hours to get customer instances back online, with all but a "small number" of instances restored within five hours.
“This incident impacted a subset of instances in a single Availability Zone,” said Amazon spokesperson kay Kinton. “Most of that subset of instances were back online in 45 minutes.”
The issues started at 4 am East Coast time Wednesday, and affected one of the three availability zones in Amazon's East Coast operation. The zones are designed to provide redundancy for developers by allowing them to deploy apps across several zones.
"A single component of the redundant power distribution system failed in this zone," AWS said in its status report. "Prior to completing the repair of this unit, a second component, used to assure redundant power paths, failed as well, resulting in a portion of the servers in that availability zone losing power. Impacted customers experienced a loss of connectivity to their instances. As soon as the defective power distribution units were bypassed, servers restarted and instances began to come online shortly thereafter."