On August 5 some customers at an Internap Network Services (INAP) data center in Boston lost connectivity for 1 hour, 20 minutes due to a battery failure in a DC power plant.
"The DC plant was responsible for powering network equipment for both Internap and other carriers," Internap said in a statement. "In some cases this network equipment was used by our customers for IP connectivity. The failure was caused by a utility company power interruption that cause the DC plant to fail over to battery backup. DC plants do not afford the ability to simulate load via a load bank as can be done on a UPS or generator. However, in this instance, when the batteries were called upon, they did not carry the load. The batteries had not shown any prior signs of pending failure during normal testing and are still being investigated at this time. Since the incident, the source of the power fed to the networking equipment was changed to UPS-backed AC power to avoid any potential repeat of this event."
The incident underscores the importance of battery maintenance and monitoring. Mark Fontecchio at Tech Target has a story that looks at four ways that data center managers can extend the life of their UPS batteries.