Fun fact: the Jeff Dean Facts was started by Kenton Varda (kentonv around here [1]), as a joke inside Google. He has expressed regret that it eclipsed Sanjay Ghemawat, with whom Jeff Dean basically did pair-programming with.
"Once, in early 2002, when the index servers went down, Jeff Dean answered user queries manually for two hours. Evals showed a quality improvement of 5 points."
Basically, he had a server that did code indexing running on his workstation. If he didn't login and run a command to refresh his prod credentials every day, the server would lose its ability to talk to prod (as it should) and fail. Much of the company depended on that service. Eventually it was moved to prod.
https://github.com/LRitzdorf/TheJeffDeanFacts