Behind the scenes: This week's WebMail outage
A departmental machine (with its own problems) was the beginning source of what became problems for WebMail. The departmental machine was sending requests for data to a central file server; however, the requests were corrupted because of failing hardware on the departmental machine.
The file server was unable to fulfill the corrupt requests but dutifully kept dedicating more of its resources attempting to process the requests. In time, the file server had no resources left to
allocate to WebMail's requests. At that point, WebMail slowed to a crawl and was inaccessible.
Similar problems caused some of the web servers to be inaccessible as well.
The machine at the source of the problem was blocked from Internet access and brought in for further analysis.