Cisco outage caused by human error during maintenance

It caused an electrical overload that also cut redundancy measures

Wednesday's three-hour outage on was attributed to human error during preventative maintenance at a data center, Cisco Systems said Thursday.

In an update on the outage to its official blog site posted at 1 a.m. EDT, Cisco said "human error caused an electrical overload on the systems."

As a result, the company's site and a number of other applications went down, Cisco said. appeared to be offline for three hours, from about 2 p.m. to 5 p.m. EDT Wednesday, according to several users around the U.S. Some users said they had been trying to access the site for training classes or technology specifications for their own Cisco gear.

Cisco said that the severity of the overload also affected redundancy measures that might have kicked in to keep the site running, or bring it back quickly. The company, however, said that the system "shut down as designed to protect the people and the equipment."

No data was lost and nobody was injured, Cisco said. In an earlier update, Cisco had simply called the outage the result of an "accident" in a San Jose data center. No details about the exact nature of the error was given.

Cisco also said it has plans already under way to "add additional redundancies to increase the resilience of these systems."

Several bloggers at noted the irony of the world's largest networking vendor having a three-hour shutdown of a site regularly used for updates for their businesses. However, one user disrupted by the outage while trying to do a voice-over-IP (VoIP) training session for federal government clients in Ohio said the outage was rare.

"I have used their Web site for over 10 years and I can count on one hand the number of times its been offline," said Lawrence Brown in an e-mail to Computerworld after noticing the outage during that VoIP training session. He said he frequently uses the Cisco site as a test site to bring computers online.

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